Some extremely popular games, like all the Hoyoverse stuff (Genshin/ZZZ/etc) or most of Blizzard's games, have their own launchers and aren't on Steam. So gamers are certainly willing to use non-Steam platforms and launchers if there's a reason.
That didn't stop overwatch 2 from eventually making its way over to Steam. They also have the best integration, once your steam account is linked to your Battle.NET account you don't have to even think about the launcher
