2-Player Co-op

Recently, my friend returned to PAD, so we were collecting stones together to pull a lot in the Bleach collab. But the 2-player co-op is way too weak! Why is there still Super Awakenings invalid? I don't get it. If playing alone is overwhelmingly stronger, what's the benefit of 2-player co-op? You're not going to tell me about stamina now, are you~. Devs, please do something about it!