The goal for Echo of Eons is to put it straight into the garbage can, preferably with Lion's Eye Diamond, then casting it with the mana produced by the Diamond
Within Tempo and Control builds, Claim the Precious is better than in an aggressive sacrifice-style deck
This is down to the three all-new, mechanically-unique legendary creatures it brings to the table
If you do happen to have a first-edition, holographic base-set Charizard, youre not guaranteed thousands of dollars
Forcing him to attack is a necessary way to prevent his ability from getting too out of control, but even then, there are plenty of ways of giving him some evasion
If you want a peek at how a three-mana Lotus Cobra that also finds you Omnath or Solitude works, check out Sato Hisaos Top 8 list from a July event at Hareruya