Yes. Ideal? No, but its perfectly normal.
Whats with them? Perfectly fine. Some want just help with creating notes (and yes, thats help as well), some just want to add trees, some want just to add street lights and some want to add everything.
Yes. If i’m somewhere on vacation or i see something when checking on something someone have written in the forum, i open a note. And i will probably never visit there.
Not in my opinion, but to be honest, its not completely clear whats ultimately the goal. But, in my opinion its to give hint about a problem on the map. Either its something missing, or something needs to be changed, … whatever.
So yes, if someone decides to just open notes, well, yes, its a bit weird(to me!), i would try to encourage them to map something themself but i don’t have a problem with the fact itself.
But, we stray, this thread is about anonymous notes and i think they are good and needed for osm.