Pretty much what Nazrin said.
I too was wondering if I should stockpile some of the 3*. This event as bad as it is, is the first event ever that gives us gacha characters, other then the event girl. Even if they are just 3* - this is a great way for newer players who joined recently to get some firepower without the need to spend Flower Gems and such.

Now the dilemma becomes whether to expand character sheet and keep em for the material used in the Blooming effect, or whether to get rid of them, since that type of Update is good Year+ from now on, and they just uselessly clog up the inventory spaces.