Originally Posted by
Kurenai
CV is the most versatile debuff unit I have seen around. I like how she is able to fill a support role (buffing/debuffing) and as a secondary damage dealer. If you're looking for a solid debuffer in general, I'd recommend her.
As for Sedum, my issue with her is that aside from lacking a skill activation buff, a lineup with decent attack debuff barely have need for her negate (only good for 1 hit per character anyway). If between Sedum and White Tulip, I prefer White Tulip.
Eligible characters become on par with gacha rainbows after synthesis as their stats, skill effects, and abilities improve to rainbow-tier, so having become actual rainbows, they'll be generally treated like their gacha counterparts. Not a bad trade-off, really. Some of them become absurdly strong, even. Exhibit A: Rainbow Rose.