Should your parents had had sex and made you? No one really cares.. Much like the stupid regurgitated topic in this thread. TKO6:deal
If the cut or cuts came about because of effective aggression (especially if the injury was the result of a sustained and prolonged attack - rather than for example a single shot) and if the damage was such that it was unsafe for the person concerned to continue then yes its a decisive victory. Not sure what else you could call it. (Lewis TKO6)
Just like every other kind of stoppage it depends on how well the winner was performing before his opponent was stopped
Win on cuts is purely comparable to a win on a lucky punch. Both are wins, if you don't wan't to get cut or KO'ed, don't take more heavy hits than you can handle.
In boxing, you win if your opponent is unable to continue due to facial damage.. So yes it is a victory..