I'm guessing it's mostly automated. Are you being used by a popular software package that you know of?

I wouldn't be surprised if the plain-text ip was used somewhere. Anecdotal evidence but I myself use that for most of my scripts to get my own ip.

A github search shows over 1000 code results.

Are you able to at least break even in terms of costs?

Why no gzip/brotli the content? Does it not help because html is small?