Well, they are picked up at night by a truck, taken to a facility to be charged overnight, and deployed back in the morning. I believe they have GPS and remote locking/unlocking function.
For example, the ones by Rappi only work from 7AM to 10PM (if I remember correctly - it should be during daylight) and get disabled in case of rain. They should be rode using a helmet, but nobody actually checks.
In the US, you can get paid to charge them in your own home. But in Buenos Aires there is no such option. I am not sure about the antitheft system beyond this.
Personally, I have never ridden one and I don't think I'll ever will, as I have balance issues.
But I can't help think that those people riding a scooters with headphones on, in the middle of Avenida Scalabrini Ortiz are playing Russian roulette.
One should really have very little consideration of their life to ride so carelessly.
I think the issue with mopeds here is that they are easy to steal. There are bikes, but most bikes are crappy delivery bikes, as it would be risky to pay a nice bike overnight on the sidewalk here. I guess Splinter has more to tell about the subject than me.