I run that service, and, so far, no issues. It's definitely not secure against server takeover, but it's much easier than making your own switch reliable.

All that stuff looks fun, but I'm utterly terrified at the idea of it malfunctioning. Like, in a false-positive way. And, as a professional deformation, I guess, it is basically an axiom for me that any automation will malfunction at some point for some ridiculously stupid and obvious-in-the-hindsight reason I absolutely cannot predict right now.

I mean, seriously, it isn't a laughable idea that a bomb that will explode unless you poke some button every 24 h might eventually explode even though you weren't incapacitated and dutifully pressed that button. I'm not even considering the case that you might have been temporarily incapacitated. People wouldn't call you paranoid if you say that carrying such bomb is a stupid idea.