Imagine you check into a hotel, and want to use the in-room TV as your display. There is probably a set top box there with an HDMI port going to the TV. You would be able to unplug that and plug it into your Flipper One because it has a full-sized HDMI port.

Go to any store, and look at what cable they use to connect their POS computer to the display. It's probably HDMI.

For better or worse, HDMI is extremely ubiquitous.

In contrast, I have never owned a USB-C to HDMI cable, and I don't know of any device except perhaps my phone that might be able to make use of one.