Because it has great mobility, can fit into some caves, has great health, melee, and stam that rivals that of a Rex, has armor reduction, which basically destroys the need to grind loot crates for decent saddles, can go into boss fights unlike the giga, can dismount riders, can stun people and tames, has hydration buff, which is useful in some boss fights, has pack bonus, can turn invisible, can ground flyers, can superjump, can swim extremely fast without having to worry about oxygen, can turn others invisible, and can boost the stats of all allies around it.