They suck when Kalindra is banned because they have crappy 4 stars. Kalindra is banned practically every week. And one of their staples is an LD, so if you don't have him they're suddenly a little less viable. So yeah, I would not recommend them to an inexperienced player.
^ if you play them unpredictably, you have to burn more pills AND fewer damage, not very wise. also, their ultimate weakness is TURN ONE. If you face something with powerful effects (aka poison/heal) you are so dead since nothing really works well for frozn. tho they are used in half decks, the other half is often not powerful either (pussycats, vortex) yah and crappy 4*, tsuka is ok but does not cut it
Frozn may mot be the most powerful ELO clan, they are strangely entertaining.
While the above poster is correct, playing your Frozn unpredictably is costly, it is also frequently the best path to victory. I don't like Mono Frozn, but turn one has options like Haaken, Sah Brinak(as a bad Hawkins), a throw away 2 star, or Tiwi Ld. Today's addition of Eliska is an automatic replacement for Tsuka who will probably never be heard from again. Frozn does suffer without Kallindra, but both Thorpah and Ayah are solid. Typically people duo Frozn with Vortex or Pussycats but you shouldn't limit yourself to those two. Draw Thorpah and Brianna together and see what your opponent has to say about that!
Generally because they work only half the time. The best option is a half deck. Also because having a lvl 5 star with the bonus acitve is vastly better then that of a lvl 2. Having high stars in your deck is generally better.
I myself find that Vortex works best for this case because not only do they offer a recovery bonus, but also have some of the best 2 stars because of this ability.