The toilet still flushes when you are far enough away so there's always at least one flush. In fact sometimes it flushes if you lean forward for one reason or another, thus creating an extra flush (and an "accidental bidet" effect). Sometimes it even flushes when the stall door opens and closes. Certainly no water savings there.
The electric sensor tends to be mounted somewhere on the water pipe, meaning that if the toilet seat is up for any reason the sensor is blocked and doesn't trip. This means that people tend to always leave the seat down even if they're only going Number One thus creating (as Cheech and Chong called it) "sticky buns" for the unawares. That's just icky.
And if you want to follow the water saving rule "if it's yellow, let it mellow, if it's brown, flush it down", forget it. Walk in, do your business, walk away and there's always a flush.
So what's the point? Time to get rid of the things.
Automatic sensors on the faucets, now that's technology with a purpose.