[ShortCipher5]

I think that's a good point.

A common tactic now is to have this idea of lock-in. That if you don't continue to use said service you loose everything. This forces you into that subscription and makes it extremely hard to transfer and move.

I have seen many apps that lock data export behind enterprise subscriptions - that have no pricing and only "contact us".

I do think there are times it may make sense to have some unique file format (maybe your app does something special and needs that format) but there should always be a way to get that data into something more standard. Whether that's a text file, a CSV file or something else.