GoKawiilYou should also consider refresh rates, which affect the fluidity of movements on your screen. Typical monitors and TVs are locked at 60Hz. That's fine for spreadsheets and more static content, but if you like fast-moving video games, you'll benefit from a display with higher refresh rates like 120Hz. It's much easier to find a cheaper monitor with a higher refresh rate than a TV.
Then, there's latency. That's the delay between moving your mouse or hitting a button and seeing that action on screen. Monitors are built for this. TVs generally aren't, so the image can noticeably lag behind your input. On a monitor, you're looking at a 1 to 4 millisecond (ms) delay. On a TV, that jumps up to 9ms to 12ms. Doesn't seem like much, right? But in an online game, that lag could make all the difference. Low-latency TVs do exist, but you'll pay considerably more than for a monitor with comparable specs.
Color space can be a problem as well. TVs with HDMI 2.0 inputs are limited to 8-bit color at 4K 120Hz. That's usually the case with older TVs, or really cheap ones. Someone looking for greater color depth — including 10-bit or full Dynamic HDR — will only find it on TVs and monitors with HDMI 2.1 support. If you're a photo or video editor, this will matter most. If your display can produce more shades of red, green and blue in each pixel, that will mean greater color accuracy for your content. Even if you're not a pro, those extra colors will make those home videos look all the more vibrant.