I used a journal app that worked like this for a little while. I ultimately stopped for a couple reasons.

1. It didn't allow editing of past posts. It was on the roadmap, but never came. To fix a typo or something, I'd have to copy the note, paste, fix, post again, delete the bad one.

2. I was always worried about putting anything important in there, as longevity was always a question. There was an export option, but if I remember correctly, it was in JSON. Which is fine I guess, but the idea of having to write some kind of parser to take that and turn it into something I'd actually want to put into whatever solution I might have in the future kind of annoyed me.

Does your app allow for editing past posts? How is data stored, markdown in a folder I can simply browse, or some kind of DB?