Enters or attacks is the key here: You get a trigger each turn that grants access to a bunch of extra cards, while it converts cards you dont need or cant cast into extra damage, sometimes up to 10 per turn with the right boardstate
Beside being very effective from a flavor perspective, it really opened the door to the idea of having +1/+1 counters evolve out of something less tangible
Only creatures and lands Cards that mill yourself "Whenever a creature enters the battlefield..." triggers Click here for a text version of this decklist Click here for my EDH Commander decks
If you still recall the early Pokemon games designed for Nintendo handheld consoles, then you truly appreciate how popular the DS was back then
However some have the argument for the card it represents 'racial cleansing'
Recochineo bestial - Las otras Araas, Jabales, Murcilagos, Osos, Aves, Felinos, Perros, Ranas, Chacales, Lagartos, Ratones, Nutrias, Conejos, Mapaches, Ratas, Ardillas, Tortugas y Lobos que controlas obtienen +1/+1