Being able to steal a players commander is often one of the most impactful plays in the format, and being able to do it for a measly two mana makes it clear that this card surely deserves its over-$200 price point on the secondary market
And the card draw trigger gives your 2-mana commander some late-game relevance
It can helm a Commander deck, it has to be exiled or dealt with in a way that doesnt kill it to get rid of it, it has card advantage built in via combat, and even has llamas in the art
And yet, its still not pricey enough to reach the top five
If cards become worthless, many fewer packs will be opened
Impact Tremors on a creature is exactly what a Goblin deck wants, because they want to dump a million creatures into play and if the rest of us are dead before the attack step, oh well