Theyre a unique collection of creatures that each act as hivemind, giving each other sliver a buff (usually in the form of a keyword ability)
But they can only attack their owner, so that's a bit of a brake
Official Pokmon TCG 30th Anniversary expansion
In other words, any time you attack youre putting a ton of pressure on your opponent where they have to choose between taking the damage or potentially giving you cards
LaPage states that those in favor of legalising silver-bordered cards argue they're in-keeping with Commander's identity as "the fun, casual format that doesn't take itself too seriously" and because "many ideas and mechanics that used to be silver-border are now printed in black-bordered sets, sometimes 1-for-1"
In addition to brute strength, Charizard is famously known for his belligerence towards his Pokmon trainer Ash, which became a running gag in the anime series