Fusion substitutes (King of the Swamp, Versago, etc.) are a thing. Which can come in handy if you're still grinding Stage missions and need easy Fusion Summons. Certainly not SUPER-necessary, but it's not useless either. The third is much, much less useful. (Though Fusion Recycling Plant makes it vaguely possible to realistically do.)
This monster has been a powerfull ally back in Forbidden Memories, is good to see this card again.