This is VALUE in capital letters
Abuelos Awakenings ban almost completely shut down the then-popular Omniscience decks, which used Abuelos Awakening to reanimate an Omniscience and allow you to play the rest of your cards for free
It enters with two additional +1/+1 counters on it if it's a creature
Ive played Tomb of Horrors Adventurer, and it really is quite powerful, being able to copy any spell is sweet, especially if the second spell you cast is a creature you get a token copy, or two of them if youve completed a dungeon
SEC cards (Ace, Blackbeard) are safer than SR leaders because their value is split between competitive and collector demand
The ability had already triggered, so what happens to that noncreature spell now is irrelevant