I dislike the argument that Smart Hubs should not use WiFi

I first ran into this with Hue. And then Tradfri. And now most recently it seems like Home Assistant might be getting on the band wagon. 

I'll try to keep this rant short and focus on the following areas:

• WiFi is probably the most popular mainstream protocol at the moment so you either need it anyway or also need a hub if you don't support WiFi control which increases end user costs
• WiFi is not the only smart home protocol, so it isn't necessarily a congestion issue
• Most smart home communications to the hub are short and bursty which is just fine over WiFi
• Best argument? Interference/Cost.

Tackling those in order. While I think most enthusiasts probably use BTLE/Zigbee/Matter/Thread/Z-Wave the fact is that most smart home users are not enthusiasts and more of them buy primarily WiFi devices. They are easier to sell and setup because they don't require a hub. Usually an app takes you through setup and then your smart home hub communicates either directly or through a 3rd party API.

However, if WiFi is such a common standard and your smart home hub lacks WiFi then you are more or less guaranteed to need an external hub to talk to those devices or you need WiFi in your hub anyway. So, you're not really saving the user money. And if you're making the user buy a an external hub with that protocol, it doesn't make the performance of the network better simply because your hub is not relying on WiFi. 

Spoiler alert; It actually makes things worse. And potentially MUCH worse. In the best case scenario, that external hub also has a wired connection and you're using it. That being said, you still need to go from the main hub to the external hub which then still needs to make a wireless call to the devices. And in the worst scenario, the external hub is not connected via ethernet. In which case you make an initially wired call which then routes wirelessly to the hub so that it can make a wireless call to the devices. Brilliant! By trying to eliminate "slower and unreliable" Wifi connections you've now created double the necessary Wireless calls and tripled the number of calls overall. Victory is yours smart home hub providers. You have clearly made life "better".

The second point would be that some justifications are around network congestion and performance. More devices on the wireless network means less bandwidth and more interference. There are, of course, 2 issues with this. The first being that not all devices are wifi based. Smart home hubs are, I think generally, a smart home enthusiast device. And so I think you'll find most dedicated smart hub owners are using some other protocol. So congestion/interference is not as big a deal. 

Regarding performance (essentially covering the 3rd point); What is the latency and speed on the network in your house and how large are smart home commands being sent? Answer; negligible.

My connections to external gaming servers is in the realm of 100ms and lower. And that is latency OVER my network PLUS the latency to reach their servers which can be hundreds of miles away. As a joke I just pinged the Wireless interface of my pi4 running Home Assistant. Average latency? 5ms. And the packets sent to that device would be puny. More less than 1kb. In short, the data will make it to the hub and be processed faster than I would ever be able to notice. 

In short... IF there is any noticeable delay it is caused by processing speed on the hub itself or on the device itself.

The only data I ever send to my smart hub which is larger would be smart camera data. I would say that most good hubs typically just receive periodic snapshot updates unless you're viewing a single feed and even most slow networks can easily handle streaming HD video to multiple devices. So again, not feeling the argument.

So why are so many hubs REALLY jumping on this bandwagon? My best guesses are interference vs. cost and aesthetic. Interference is worse the closer two sources of interference are. Better shielding things like external antennae can address this, but those things increase cost and/or make the devices less attractive. Given that shielding typically just means "better components" I would say it truly boils down to cost. The cheapest way to eliminate interference is to simply not include any source of interference which you can rationalize away. 

I suppose I should end this with a bit of a talk about my own setup. At "peak network load and inefficiency" I had Home Assistant running on a server which was hard wired to a Nest Wifi node (but not the main node, so it was actually a wireless connection) a Tradfri hub connected to the same Nest Wifi, a Hue hub connected to a separate, but also satellite node in the network and an August Hub connected via the cloud, via Wifi.

Connected to those were about 70 devices between lights, switches, locks, outlets and so on. Most are Zigbee based. And then there are also 3 EZVIZ cameras which I believe HA is talking directly to over IP (aka, over Wifi).

With this setup, which I think would easily put me into the top 5 percentile for both # of devices and complexity, there is effectively no delay. I click a button in the UI or a physical button and the response "feels instant".

I also recently moved some of my servers around and switched to a Skyconnect to retire both the Hue and Tradfri hubs. Performance feels identical. And this makes sense. As I've said, latency within the network is so low it doesn't add a measurable difference.

External response times may be slower but if I'm not in my house and a call is delayed by an extra 100ms am I going to notice? No.

Please don't mistake my meaning here. I am not saying that there is no value in these sorts of devices. My problem is solely with the pretense that the decisions aren't being made for financial reasons but rather because they have a positive, tangible impact on the experience of the average user.

I would have ZERO issue if the devices were being advertised as only being intended for that small group who needs or cares about the minimal benefits received. But they aren't.