I think real POE is kind of heavyweight. It uses higher voltage like 37-57 volts...

I think real POE is kind of heavyweight. It uses higher voltage like 37-57 volts and the pi poe hats I've seen usually have fans.

I've used "informal" poe where you have a cheap injector/splitter that puts a nonstandard lower voltage over the ethernet.

but real poe is getting more popular, poe switches are becoming available and maybe the hat is worth it.

There are also middle-of-the-road solutions:

basically poe splitter that has a usb-c power out for the pi