I have a portable external monitor with two USB C ports. It can get power and video from one USB port.
I can plug it up to my iPhone 16 Pro Max using the same standard USB cord. With a phone, it can only power the display up to 50% brightness by itself. If I plug power into the second USB C port, it will show the display up to 100% and charge my phone.
Having USB C also means I can use a standard USB C to HDMI cord for TVs and use the same cord for my computer. Not to mention all of the other standard USB protocols like audio, mass storage, Ethernet, etc. that just work.
It's also funny that the Lightning to HDMI adapters had to add hardware to decode a compressed video stream from the Lightning port.
It's basically a wired AirPlay adapter. That's why they cost so much.
Lightning was meant to be a software-defined serial data interface, I suspect because of the confusing breaking mess that was the 30 pin adapter over its lifetime. The digital logic to work with hardware was pushed outside the phone into the cable.