This doesnt have to be a combo more often than not its just a direction if the cards in your deck all point in the same direction that is to say all work to achieve the same goal, whether thats stockpile and use energy, mill them, give you a bunch of tokens and swarm or Craterhoof them or any number of ways to win, the deck is more effective than a jack of all trades, master of none approach and that was a seriously long run-on sentence, I apologize
If you spend to cast it, your whole team gets +1/+1 and can get in damage the same turn, which is perfect for a surprise push or for finishing right after you rebuild
And if Mobilize decks gain any kind of traction in Standard, Sephiroth is going to be trivial to transform
By caging cards, it borrows their activated effects, letting you piece together wild combos
With regenerate, you can always protect Ink-Eyes from destruction and keep landing those devastating hits