If this is true then the reason that a console would be better than a custom PC is that it would also be designed to work better for that purpose. Turning on the device when the controller turns on and sending CEC commands are two huge things that aren't well supported outside of the console space. Also it would likely run a trimmed down version of Windows and would be set up to "just work" in a way that a system that can have any arbitrary set of hardware will never be able to do.

But the really nice thing about the concept of treating a PC and console as the same platform is that you don't have to worry about why people might prefer to go the route of buying the console. You can go with a regular gaming PC if that's what you prefer and your library will have all the same options.