I mean, it is a completely valid playstyle to just use Tulu for everything, but that is definitely one of the more boring approaches. I designed them so that there were many valid playstyles to use. I mean, there is even the sac method, the auto method, and other options.
Like, one totally valid way to play is give Tulu the auto necklace and use the concentrated antidote or antidote bomb to kill both Nol and Nara at the start of each fight. Another strange, but valid way to fight is to use Tulu's insanity on all the enemies, then kill both Tulu and Nol while Nara spams her avoid skill (this doesn't work on bosses). You could even go a bit crazy and have Nol just spam pops against smaller groups (We are pop stars now! Once you pop, you just...).
There was no wrong approach, really and I made some of the more broken non-ult playstyles a bit harder to figure out. Really, I wanted the players to be able to have their own unique experiences with the exception of the Jest enemy.