Heroic Intervention is widely played because it protects your board from most removal at instant speed, granting hexproof and indestructible. Commander tables are full of sweepers and targeted answers, and this card can single-handedly swing tempo by saving your entire board. It is now a staple protection spell in many green decks, appearing frequently in EDH staple lists. As more board wipes are printed, the premium on this kind of cheap, flexible protection only increases.