I run a business that makes 3d printed braille molds that are used to repeatably emboss paper. I haven't considered the molds being offline storage, but I suppose they are. I mostly operate with the assumption of a shelf life of 10 years for the PETG molds, but ink free, embossed paper has excellent lifespan if stored correctly.

I guess you could consider it an "offline datastore as a service." It would be a pretty good offline storage of keys with a way to request a paper copy. Certainly issues of trust and physical security but wrapping it with encryption would be easy. Also benefit from your government's legal protections for mail. There might actually be a usecase here.

Couple fast facts:

- Current 26 * 32 = 832 cells * 6 dot braille = 4992 bits/mold/page

- Possible 28 * 34 = 952 cells * 6 dot braille = 5712 bits/mold/page

- Maybe some more headroom, but that's what is possible with current spacings