OW2 can already run without Battle.net running, but launching it through Battle.net takes care of auth for you. Presumably they will modify the Steam OW2 client

OW2 can already run without Battle.net running, but launching it through Battle.net takes care of auth for you. Presumably they will modify the Steam OW2 client to include the Steam lib and handle auth via Steam. I think it's actually reasonable to have hope that Steam can launch into OW2 without B.net.