Eldrazi are one of the most popular creature types in Magic, so there's always going to be some kind of value to them
Thanks to converge, it can hit nearly any nonland permanent at low mana valuesplaneswalkers, creatures, artifacts, you name it
You can pat yourself on the back for clever use of the legend rule to be your sacrifice outlet, and yes you come out with a measly one treasure per transaction, a lot of other triggers happened along the way, when a creature dies, when an artifact comes into play or is sacrificed, those payoffs can win you the game
However you rate your Lilianas, the Last Hope is one of the premium walkers in cube and certainly one of the most played
Formats like Commander and Pauper started out as fan variants that eventually built up enough steam to get official recognition
Other than being a fine standalone value piece, it doesnt do anything particularly synergistic with the rest of the deck