Here's an example of a meme that would be terrible if converted to text only.

I agree that some things, like simple tweets, one liners and some chats can become text only, but even then, it is easier for people to take a screenshot and repost it, rather than copying the original text and giving the proper credits.

Another thing is, say there is a small thread in Lemmy and someone said something funny. A person screenshotted it and posted it. Then another user pointed out that their "username checks out", or something, which the original screenshotter didn't notice. If the screenshotter only copied the text, people would have missed the username is funny thing.