What's so dangerous about UWP ?

Yes it has it own limitations, however Xbox 360 or PS3 for example had far less memory and processing power available in general.

But it’s not. Microsoft has talked about it past years and at Build 2016 event they said that later this year Windows and Xbox markets will be merged (or all Windows 10 devices). The current dev mode for Xbox one is for developers to preview/test their apps and games. I’m not sure if everything will be available everywhere in the end but that was the plan.

A lot of the Android phones don’t have either and it’s more wild west than WP is. However I think WP is dying now for sure when Microsoft killed their own production. That does not rule out all the other UWP devices including which will be up to developer to decide how to use the capabilities of the device.