Neither; in fact quite the opposite. It's a -second- evolution; not an alternative to the first. You have to evolve a unit (then level it to max again) before you can "bloom" it. And no, it isn't in for most girls; right now only the following units can be bloomed: Sakura, Cherry and Evening Primrose.
Have people already done this and can confirm that the blooming works properly? I have all materials for Sakura now but i need some kind of confirmation first.
I have 2nd evolved Evening Primrose, but she's still far from her max level, only 23/80.
one of my ally's cherry is already evolved lv 70.
Remember: allies are capped at the highest level of your characters. You won't see any 80s until you have one of your own.
you dont have to keep someone's affection before 100% to wait for the second bedroom scene, you'll always be able to watch it through the Collection tab
Thanks for the confirmation guys. Just bloomed my Sakura and brought her to up 98%. I hope that we will also get the 2nd affection scene soon.