Ok, let's give examples
I will use one example, i don't want to spend lifetime posting thousands examples anyway between us, but this one is good for me, at least to understand better.
Here is first Andromeda image done with a full frame DSLR and a lens from Bortle 6 and 7 hours by one imager well respected:
https://www.astrobin.com/187996/?active=21194
And here is another image of same target using same lens but with a cooled mono camera small sensor from Bortle 7 under nearly 5 hours by same imager:
https://www.astrobin.com/278800/B/?page=2
To my eyes the second one with smaller sensor is nicer and better, and regardless it was Bortle 7 slightly worse and less time it was better than from a full frame and Bortle 6 from same person, same sky but it went from bad to worse as he is living under same sky anyway.
Funny that he went from full frame to cooled cameras, and i didn't see him went with a full frame camera but he went with a scope that gives 88mm image circle or almost full frame reduced, what is the point then? instead he went with a CCD i believe not a full frame either.