I concur with this statement. Nothing extra is useless and you avoid it just cause you have another alternative to use.

My setup at home is currently

Synology NAS - To Host all pictures, and some very big videos / videos that are not available to stream elsewhere. (well the primary aim for the NAS is for file backups)
MiniX Neo U9-H - Run Kodi, android apps.
Samsung Smart TV - To run Youtube 4k/Netflix 4k.
PS4 Pro - To Game.

MiniX , PS4 and Samsung TV is able to output HDR, but due to HDR tech being new, there is nto much *ahem* source of HDR (if you can actually find any outside those tech videos or short clips)

In fact the best HDR source for now is still Netflix/Amazon Prime, even Kodi dont have HDR video source outside those small clips.

And yeah derailing from the subject in hand of Android Box XD
I'm still sour that U9H has no native support for 4k Youtube/Netflix hahaha, since it is using those open source Android instead of paying royalty for using Android TV (however if android TV that you're stuck with apps only authorized to use for Android TV instead)

So pro and con go, thankfully my TV can fallback to Netflix / Youtube 4k HDR.

IMO, it remains the benchmark.. My minimum. As for market price.. Check online stores and garage sales thread..

Can be done.. YouTube howto...easy.