I've seen this question pop-up a few times but haven't really seen a suitable answer. I think Logos is great, but if ever it goes down or I move onto an OS that doesn't support it, I would like to know all the notes I've taken and work I've done won't just disappear.
I think Markdown as a format has helped eradicate this as a problem in the open-source community, and would be an incredible thing to implement with Logos and provide for a lot more freedom and trust in Logos in being able to archive my work.
I find it difficult to put all my trust in one program just being around for my whole life (I'm 23, so presumably have another 70 years of biblical note-taking to do) so an archiving feature, particularly utilising Markdown, I think would be highly beneficial for many users. It would also give me more trust in Logos funnily enough, knowing that they don't just care about me using the program, but my data and research being safe.