Music-wise, lossy compression takes place via a proprietary codec (ATRAC). It isn't viable for data storage (neither was CDR(W)). Trust me, I had data loss due to all of these. Just use LTO with some parity data.
Making ATRAC the exclusive and mandatory codec for MiniDisc Audio was another typical unfortunate Sony move but in my view doesn't discredit the strengths of the physical storage medium.
In this case, I believe you are right: I don't think the data would've survived without minidisc. But in other circumstances where the user did not know minidisc is lossy?
In the end, a lot of these hidden gems have been (re)released because lost tapes (and, I suppose, HDDs) were found which is neat.