How about a situation where you're recording a song with your buds/bandmates and the drummer played a few notes out-of-time or singer didn't quite sing that long note in tune. You're not going to hire anybody to replace what they did. You can have your buds come back and try and try until they get something to your standard or tell them that they're bad musicians and need to study and practice for more years and years before they dare want to record a song again (purist). Or You can just live with the bad ("shitty is pretty"). Or you could hire someone to come in and replace their parts. Or you could just take a few minutes to fix it in cubase.

To me, the central question is: is this about the composition or the performance? Personally, I spent my university time getting a degree in music composition, so getting the point of the composition across is my priority. I'll auto-tune and quantize whatever if the composition comes across better. But I could understand if other people feel differently (they are a purist or very performance-oriented).