Minnie and Katyusha are low dps, high burst dps units. That makes both of them EXTREMELY valuable for doing the Devonis Stun sHell map that comes up regularly in PoC. No other tank can make as much use out of the sparse seconds of mobility.

Fortunately I just barely managed to snag a Minnie from the Halloween event. Soviet packs have only given me four stars I already own because of course they have.