@autumn@m thats true if im correct in thinking that mentions aren't parsed from the content portion by the receiving server and only the tags part of the object
@autumn@m i just tested this so on misskey when replying directly to someone without a tag it seems itll add the mention to the post object regardless and when doing this with my pleroma account it picked that up
@autumn@m pleroma actually displays out of band mentions like that i believe (if not they deffo have a MRF that adds them to the text back in) but because mastodon doesn't at all you can mess with people with it
@autumn@m one thing i guess you get easily with in-text mentions is that untagging people from a conversation is pretty intuitive. you'd have to build custom UI for that if you had them out of band