OK, thanks for your reply. JFYI It's not what you think that will make or break your business; it's what your potential customers think, that matters.
Using email as an example, having to transfer email with drag'n'drop in something like Thunderbird is clunky, slow but works to a degree.
Having direct access to the mailbox directory on the filesystem would make it easier to transfer out/in (assuming you already have your emails in the same format).