I answered that question. That's where cross-buy comes in. If a game was made for cross-buy, you can play natively. In the case one doesn't have a game that supports cross-buy, they can at least stream. Being able to play is better than not being able to play. People have stated many times before, it's for when the TV that the xbox is connected to is being used and you want to play games, and the game you have doesn't support cross-buy, you can play it on a Windows 10 device...this includes Lenovo, Dell, HP, and MS laptops/tablets. If you aren't in that position where this scenario doesn't apply to you...you aren't the benefactor of this use case, but the fact remains is that it is a viable use case.
See above response. Also, it's not about making a PC gamer buy an Xbox. I don't know how many times people ask this question. It's about selling you games in their ecosystem so that they get a cut. They don't care if it's from Xbox, PC, Mobile, Hololens, Surface Hub, Rasberry Pi, or whatever...they want you to buy from their store so that they get a cut from sales. It is that simple.
"I feel like I'm taking crazy pills."