Well you know all that stuff that monitors advertise... response time (2ms), refresh rates, adaptive v-sync, 4k 60Hz, etc, etc.... most TV's don't have this. I think I may have once read that a TV had something like 40ms response times.
A number of these advanced features require a recent version of DisplayPort and do not work over HDMI.
Of course, a top of the line gaming monitor will cost as much as a much larger TV, so the question is, what's more important to you? If you were planning on buying a cheap monitor then maybe it won't be as bad to buy a cheap large TV. I have found it a lot harder to play on my old Gen5 LCD TV, especially when there's traffic that needs avoiding. I'd crash far more often compared to when on PC.
Also I've worked with hundreds of (business-grade) Toshiba notebooks over the years and they've been pretty stable. Only their early (revolutionary) ultra-books had cooling problems, which weren't helped by the reseller putting their support sticker over a bunch of breathing holes.