Most swords in Magic are equipment and permanents, though there are a few that predate that card type
Much like how Lukka has a bond with his monster, the companion mechanic opens up new deck-building possibilities and grants access to a guaranteed monster right from the start of the game
It returns as a 6/6 creature and can return again and again
An opponent then sifts through your deck and gives you a creature, a land, and noncreature, nonland card
#37: Future Card Buddyfight Would be higher if not for that biblically awful gray border
Its a healthy mix of current resale value, the cultural impact each card has had, and a cards visual aesthetics, and also a bit of personal preference from myself as well (so just keep that in mind)