Generally when its some singer or sports figure forced into a role its trash.
But sometimes directors use it to add authenticity to background characters like in the Wire for example. Lotta actual baltimore brehs were playing bit roles, and i actually had no problem with it in that case.
There are exceptions though, because some of these singers were triple threats growing up and went to drama schools, but i wouldn't really call them non-actors in that case, they just got on in one lane before getting on in the other. Tupac & Lady Gaga for example went to performing arts schools