If you already have a 4K TV (or a monitor if you play that way) and are willing to be locked into the Microsoft in game marketplace only and give up on community created content as hosted on sites like Flightsim.to and live with the limited selection of flight control peripherals available to a closed ecosystem then yes, it’s a good device that can run games at 4k
Oh…and there is no VR support either.
The question also remains…(especially after SU5 and the subsequent fixes)…is the Xbox actually running at what a high end PC might consider “ultra” or is it indeed just a mix of medium/high?