It may not be a good choice for long-term data storage, but I disagree that it should not be used for data sharing or software distribution. Different use cases have different needs. If you need long-term storage, it's better to avoid lossless compression that can break after minor corruption. You should also be storing parity/ECC data (I don't recall the subtle difference). If you only need short to moderate term storage, the best compression ratio is likely optimal. Keep a spare backup just in case.

For long-term archival I think relying on your compression software to protect data integrity is a fool's errand, protecting against bit-rot should be a function of your storage layer as long as you have control over it (in contrast to say, Usenet, where multiple providers have copies of data and you can't trust them to not lose part of it - hence the inclusion of .par files for everything under alt.binaries).

I keep seeing recommendations for par/par2 but it seems like as software, the project isn't actively maintained? As an aside, that makes me think of dead languages and the use of latin for scientific names because it isn't changing anymore... but do you want that out of archival formats and software?

The fork compiled for me this week, when the official 0.3 version on Sourceforge wouldn't. I vaguely remembered par3 being discussed, but couldn't find anything usable. And that's an example of why to be wary of new formats, I guess?