Some good questions - I've sent the switch back, but I'll answer what I can.
Didn't read what the idle power draw was. But they didn't get warm and they only have to run a relay, LED, and 2.4GHz module.
The mobility thing is interesting. People - even those with restrictions - tend to move around. Having two switches isn't as convenient as a switch you carry with you. It's also quite expensive to run switches everywhere.
Boot-up seemed fairly instant. If you've ever tried LIFX bulbs they remember state and connect to WiFi within seconds. There was an LED on the switch, and the sound of the relay clicking would probably alert you if there was a dead bulb. The switches still work as physical buttons even if your WiFi network goes down - so no worries on that front.
As you correctly identify - having a DDoS take out the server managing your switches would be unfortunate!
I'd get a timer, but like most people I work irregular hours.