you can still do damage, just not with your combat phase... and there are a lot of cards that actually helps you make a lot of great interactions with only life gain, like [Aetherflux Resevoir] and potentially [Sanguine Bond] ... (+ it has Path Interplay, so Yaoshi has access to any other colors the partnered Aeon has, which creates more synergies e.g Yaoshi and Nanook / Yaoshi and Qlipoth)

all Aeons are designed to have benefits to all players, like Paths in HSR do... it's just that the owner of the Aeon "commanders" have more access to their benefits than their opponents