It was no fun realizing after a few IRL visits that we really just didn't like each other unless careful email communications was our primary means of interaction.

With some folks the time it takes to write an email is all the filter is needed. Sometimes, though, it only takes 5 minutes IRL to realize that you only like the persons email - not the person, themselves.

Are these really online friends if you are also recognizing them as real-life humans that exist in the same world you do and treat them like you would any other friend? Aside from maybe the Amish (and even that's questionable if you pay close enough attention to what they are hiding), there is almost nobody who doesn't communicate with friends using electronic devices. That is not a unique property.

"Online friend" only seems like a useful distinction if you truly think of them as a some kind of nebulous chat entity, where specific implementation details be they human, AI, space alien, or magical fairy doesn't play into the experience.