I am a noob to home automation but I have a few Kasa light switches that I like. The Kasa switches connect via wifi and Google is able to interact with them. I am also interested in some smartblinds (maybe Smartwings) and I notice they REQUIRE a hub. I understand they are Zigbee over wifi. Why do some devices require a hub and others don’t?
Wifi is fine for some things, but it’s power hungry, it requires an IP address for each device, and is subject to interference from other wifi devices. If you want to block all of the devices from accessing the internet, it adds some extra complexity. If you have a battery powered wifi device, it will power itself off until activated, then have to connect to your wireless network (DHCP, etc) before it can transmit, which takes a second or three.
ZigBee, ZWave, and BLE are low power protocols, and are fairly statically configured. They use less power and can have much better battery life on much smaller batteries. When activated, they connect back to their respective networks immediately, so things like smart buttons and motion sensors are very fast.