While you can make your money if you get lucky with a Golden Chocobo, missing that is a huge loss
Spells and abilities can also destroy permanents
That's a very good advantage, and the fact that it's so cheap to play means you can do a massive amount of setup early in the game, or just a play a big monster and have it get over its summoning sickness before the opponent can do anything whatsoever
Champion of the Perished gives you a sizable beater but provides very little synergy with the actual deck, yet he keeps showing up in upgraded versions
In Wizards of the Coast's 'Bridging Worlds' video, which discussed how the collaboration came about, several Wizards' staff point to similarities between Magic: The Gathering and Warhammer 40k that made the crossover a natural fit
In 60 card the rate and protection alone are probably enough to warrant inclusion in a bunch of decks, with the upside of the toughness manipulation sometimes mattering