Uhm, frankly I'm not sure. Quick Google reveals a few differences but I'm not sure why one is banned while the other one isn't.

Snuff is probably culturally significant. Despite never knowing anyone who takes snuff you still read about snuff and snuff boxes. In fact I seem to recall that some people still call the webbing between your thumb and index finger the "snuff box" because that's where people would put the snuff before insufflating it.

I would imagine snuff boxes / accessories now days are bought more by people who snort illegal drugs than tobacco and the name remains as a PR thing (shops, even head shops with weed art in the window, don't want to advertise things like "cocaine snorter"). But I've no idea how many people still exist that use actual snuff.

Snus comes in pouches (like a teabag?), intended to be placed between your gum + inside of your lip AFAIK.

Snus is something you put between your gum and lip.

everyones talking biscuits vs cookies. I love it.

Since there’s a lot of wrong info in the responses… snus is the word for snuff in Sweden and traditionally had an extra sanitization step (boiling IIRC), which was different enough that it became it’s own term, because quality was better. Snus is almost universally used under the lip, but I think used to be used nasally too.

Snuff is just the English name, and can refer to nasal snuff, dip, pouches. Just means it’s ground up tobacco and isn’t anymore specific than that. Regionally it means whatever way of using it is most common.

Basically it’s confusing in the same way if you ask and American or European about football. Technically the word is not specific but it has very strong regional definitions