If this really is Play Anywhere and allows cross platform between Win 10 and Xbox One this game might actually be worth my while.

I have a lot of gaming friends who use high end PCs. While mine is middling at best I enjoy playing some games on the TV. This might finally allow me to play on the TV as I like while my PC posse can stick to their master race mouse and keys.

Microsoft should have done this ages ago...

I'm pretty sure they've said that every Microsoft published game going forward will be digital cross-buy between Win 10 and Xbox One. Whether or not a game has cross platform multiplayer will depend on the game, but Sea of Thieves seems like a good candidate since there wouldn't figure to be much in the way of control advantages for one system over the other in that type of game.

Rare said at Gamescom that it won't have cross platform online play at launch, but they are working on getting it into the game.

@brandondryrock: That's disappointing. I guess I can still play on PC with friends and have the option of Xbox play later down the line. It's probably a hell of a thing to shoehorn in to your game if it wasn't planned for.