While presumably a 'thin client' can run on almost anything (TV's, Phones, Tablets, Etc.) where in the 'heavy lifting' is done in the cloud, presenting an 'Xbox GUI' on these devices likely does not require much (or very powerful) hardware.
Reverting to 'Windows on Everything' concept from the 1990's with a 'Windows based Xbox' might burden any device with the bloatware that is Windows while possibly giving MS and developers a 'standardized software platform' to develop on.
However given the very wide range of system hardware configurations and performance levels found in the PC industry I'm unsure where providing a 'Xbox baseline' system comes into play here.
IMHO: the main marketing advantages that Consoles have over mere PC gaming is:
#1 is the cost and entry point – consoles represent an enormous value for the dollars spent
#2 is the 'plug and play' – it mostly just works functionality (no fiddling to get it working!)
#3 last but surely not least is the mostly 'unhackability' of Consoles providing a mostly secure platform for the worlds children can mostly safely play on.
I'm guessing that the Asus handheld being built for MS might be an attempt to provide a Windows-less Windows Xbox system.
Microsoft Gaming is earning more than a year ago, even with falling console sales. Profits from subscription services and multi-platform titles led to a positive financial report. Microsoft may change strategies again, with several rumored Xbox consoles in development.