I'm not really sure about this, I mean I don't want Buffy to go gay for the storyline after so many years of being the straight gal.
But then again this has the potential to be a much better relationship for her than her previous ones, Satsu loves her and that goes a long way to being a good base of emotional support and security. Something shes been lacking all this time having to carry the burden of being the leader.
Twilight made a point of trying to take her moral certainty from her, if anything I see Satsu bringing her more confidence in herself and her role.
I'll wait and see how this plays out, but right now I'm hoping Satsu sticks around and this storyline does go somewhere.