I prefer Lavender, Convallaria, German Iris and even Calla in such a specific Team. Bipinna is pretty much outclassed from all those Girls cause her Def-Buff doesn't synergize that well compared to the Buffs the other Girls have. Her Speed is another issue compared to the other Girls (except Lavender). But Lavender is one of the strongest 5* Events.
Also like Ivan said it's only usefull if you aren't a autorun user. That's the reason i don't participate in Dogwoods Step Up Gacha either cause it's not my playstyle. I like Skill Activation Squads (for later Bosses) and Pest Controll Squads the most.