I am a retired British Telecom engineer and worked on TXE2 telephone exchanges, Strowger electro mechanical. What I like about Sonoff devices is that they work as they should and are very reliable. I first used Sonoff basic after my wife broke her foot for controlling lights and sockets. I’ve used basic to make power inverters smart and also to modify zone valves to be smart in central heating. For our remote holiday home which is off grid I have several on off periods to reset the router and turn the router off at night to conserve power. The power on at power up should the batteries ever discharge ensures when power restores the router becomes live again.
I still have a lot to learn.