Aside from being a human, which is a very relevant creature type in Commander, Modern and basically every other MTG format, Esper Sentinel is good because it reads: Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays X, where X is Esper Sentinels power. Its a bit like Rhystic Study, but the cost can be far higher if youve got things that make humans stronger or you can put +1/+1 counters onto Esper Sentinel
In this case you become the new controller of the card, but it is still owned by the player who started with it in their deck (or the player who created it, in the case of a token)
Red Eyes Black Dragon 1st Edition PSA 10 (2002) There was a constant battle between who liked Blue Eyes and who liked Red Eyes when I was at school, and although I was a BLue Eyes kinda guy, this card never got old
Opposites was also a primary theme for that game generation, so that expansion featured cards like the full art Reshiram and Zekrom cards to exemplify that motif