Because of how we go event -> break -> repeat freemium players will quickly run out of silvers for awakening material (I'm on this boat now ;_; ). It's always nice to have more units for more variety and free players only have the choice of Ricardo (who's not too good) and Saki for ranged melee units unless you spent crystals or were lucky to get Sabinne or Hina from 2K gatcha (you can get plats from this, it's how I got Lyla).

Personally I wouldn't worry about trying Crystal Keeper G unless you have 2 Artillery Officers (Percis, Zola) for the last wave of eyes since it will be a long while before we get Swordmaster Sandra.