There are some limited uses where I really wish this was the case.
I work in 911 dispatch, it happens way too often that someone calls for an officer to come out, then when they get out there the officers can't find them- no answer at the door, they're not waiting near where they said they would be, etc. and there's no obvious signs of an emergency So they have us call them back, we get no answer, and the officers have to leave.
Then a little while later they call back irate because "the cops never came"
We pull the incident up, tell them that yes they did come out, they couldn't find you, and you didn't answer your phone, so they had to leave.
And then they'll be like "well my phone was on silent, so I didn't hear it" or say they didn't answer because it was an unknown number.
We could probably avoid some of these if we could turn their ringer on from our end and set the ringtone to a message saying something like "you are receiving a call from 911, please answer your phone"
I also wouldn't mind being able to remotely turn on speakerphone, because some people like to put their phone down and walk away from us even though we're still trying to ask them questions or give them instructions. At least it might let us hear what's going on better even if they're refusing to talk/listen to us. And occasionally people can't figure out how to turn on speakerphone when we need them to when we're trying to do something like CPR where they need to able to listen to us and have both hands free.
Might also be nice for pocket dials, we get way more of those than you'd think.