I just run some simple services such as Audiobookshelf or Wallabag behind a reverse proxy. After reading the other comments, it does not look like there would be any benefit for my use case.

Yes, I have always used a reverse proxy which seems to eliminate the need for multiple IP addresses. It seems like having multiple IP addresses just creates additional cost and complexity, but I have seen many VPS providers offer multiple IP addresses, so I was curious if there was a use case that I was not aware of.