You plug in an HDMI cable, it either works, or it doesn’t. It might only work at specific resolutions, but you get immediate feedback when it’s working or when it’s not, at whatever resolution you try.
You plug in a USB-C cable, you might get a quick charge. You might not. Unless you have a USB-C power meter, you have no way to tell unless you know how quickly your device should charge in 5, 10 or 15 minutes, and hang around to wait and see if it does or not.
