I mean think about it…when was the last time you heard of charity gutter cleaning services? People would much rather enjoy their leisure time on hobbies or with family/friends.
In terms of charity cleaning services, there are people who clean hoarder's houses or landscape unruly yards for free on YouTube... ;)
For free on YouTube in exchange for ad revenue
If the government gives out free money people will pocket it. Should not be controversial.
As for why: for purpose, for praise, for community, for mental health, for trade/contribution, for skill building, etc. Loads of examples of this already. Maybe none of these things are attractive to you but I don't think that's universal.
Like I said, it's just trying to add to the default UBI, not getting everyone volunteering in their community or else.
I can imagine loads of tasks or jobs that would be quite pleasant if it weren't for stressing over efficiency or business admin.