Originally Posted by renchon

but she's evolved. should i remove her ? Rosa Novelis and other Mage evolved too.
yeah i know her speed is bad

Bronze units that are evolved can keep up with Silver for a while, but by the time Silvers hit Evolved level 15 they'll have caught up, more or less, to a Bronze evolved 30-40. Golds will likely catch up sooner. Does vary by unit though. I personally hate slow speeds, only using them if map shenanigans demand. However, if you are depending on powerful helper squads to power you through, this changes things, as you can use slow squads on your own and a fast, powerful helper squad to blow through and reach flag (allowing your other squads to collect chests/seeds/coins without getting killed by pests).

Overall, phase out units as new, better units catch up and surpass them. Obviously rarity limits potential stats, so don't invest too heavily in bronze units (like, don't level your bronze anymore) and silver you can level but know "eventually" you'll phase them out too due to Event golds, even if you have shitty luck in gacha.