We also know Uni 6 saiyans are already biologically different from Uni 7 saiyans. One they don't have tails, do not turn into great apes, and are in general more slim. She also is not that powerful. She got toyed around by Goku in their first encounter. In their second encounter, not only is Goku weakened, he didnt take it serious until later, ands its a 2 v 1. Plus fusion is absolutely broken if you want to go into Kefla. ss3 Goku and ss2 Vegeta were nothing compared to Super Buu. Super Buu absorbed Gotanks, Piccolo, and Gohan and became way stronger. Goku and Vegeta fused and basically beat the crap out of Buuhan in base form, and as a piece of candy. Lets not forget that 2 children fused into gotanks, got SS3, a form neither individual child had, and was able to stand up to Super Buu who out classed everyone except Gohan.
- - - Updated - - -
In short Dragonball does things to please the Omniking
If its cool, its in.