there are more than enough things to do that help society, which aren't done at the moment, because no one pays for them.

I often see a lady riding her RoundABout scooter, on disability, picking up trash on the side of the road. She's incredibly nice and good hearted, and hates sitting around doing nothing. But the reason I stopped to talk to her was that it is unbelievably unusual for someone who is obviously on disability to be out doing something for the common good.

And unless you have some hard data showing people on public assistance use their free time doing the unsung dirty work society needs, I don't believe it will magically start happening if we change the name of welfare to UBI.

Not sure how that's relevant. It's pretty clear the proposal is "require people to do the handiwork of their community in order to receive a basic income."