Using a TV for photo editing

I don't know that one couldn't.  One does have to deal with the size and placement issues.

TVs aren't really optimized for use a still photo editing monitor.  My 55" OLED looks good when I display stills.  I've had it adjacent to my desktop. But the problems then were viewing angles, placement, etc.  Aside from the OLED burn-in concerns, I could treat it as a monitor.  But I didn't edit or really do other work on it, placement, if nothing else, made that almost impossible.

One can say they don't have the right gamut or color spaces, or consistency, backlighting variances, contrast, etc.  But it's capable of being set up and calibrated, it can be set for a variety of presentation purposes. So while not specifically a photo editing monitor, I'm not sure it's worse than a huge number of "real" monitors which also are less than ideal for some purposes.  Gaming monitors look for responsiveness, refresh rates but with moving game action, one may not notice limited gamut or backlighting variations, maybe contrast or black levels.  I've got a couple of older 1920x1080 cheap monitors which are fine for office work but I'd hardly call them photo editing monitors, either.

I guess it comes down to just what one needs in a monitor or tv.  Some people want their tv viewing experience in lighting controlled rooms, multi-channel audio. dedicated seating, etc.  If the photo editing is limited, one shoots in jpg and maybe crops some, etc., then the Tv may be fine.  Others need controlled lighting, critical repeastability and matching, etc.and aren't using $500 consumer monitors, either.