Get Your Head in the Game stops touching your head once contact with your head is broken
You may use mana from this creature to pay the cost of any activated ability, not just abilities of artifacts
And then, they can better counter their opponent's strategies.
Instead, you have to exile a card from your hand to Chrome Moxs Imprint ability, and Chrome Mox can then tap for any color of the Imprinted card
But in Commander, the chance of sacrificing a creature with seven or more power is much, much easier which unlocks the -7 ultimate ability where target player draws seven cards and loses seven life, doing a pretty good Griselbrand impression (which happens to be banned in the format)
While Eidolon has a creature version of Pyrostatic Pillar, a powerful burn card in its own right, Cemetery Gatekeeper is like a more flexible creature version of Ankh of Mishra