Sea of Thieves has a store page up on Steam with a release date of "coming soon".

Yeah, don't know what else to say really. Cool that's Microsoft is putting some of their exclusives out on Steam too. I wonder how well games like Halo, Gears and Ori have been selling on there.

Cool, i still haven't jumped in but i have a group of Steam friends who would all like to play it, this just makes it easier.
I don't have sales numbers, obviously, but all discussion around the Master Chief Collection happens on its Steam Community Hub and i think that's huge, you don't need the game on Steam to use those features but it makes the Windows Store version feel a little disconnected, developers even respond to people in the Steam discussions because there's no where else to do it, it's also where they post news and updates. The same thing has been happening with the Epic exclusives, if the games have a Steam page then it becomes the central hub for the game, even though it's not available, i think that's important and could translate to the games doing well on the service.