You can format a Hi-MD for data. It's very slow by modern standards, especially in random access, and the media is so rare and thus costly there's no point except for the sake of it - I only have one, and at $60 a pop I wouldn't have any except that the seller I bought my MZ-RH1 from forgot to check if a disc was in it before shipping. But it works.

A modern development of that technology would have greater capacity, sure, but I can't imagine how it would approach the low random-access latency of solid-state media.