Update: Looks like Torna the Golden Country's physical version is a proper cartridge release after all

[AHYL88]

I'm not so sure the site itself has got it right

Look carefully on this link, which has the details of the game on Nintendo's online store: https://store.nintendo.co.uk/nintendo-switch-game/xenoblade-chronicles-2-torna-the-golden-country-art-print/11858493.html

It is the physical game, WITH a download code for Xenoblade Chronicles 2 Expansion Pass, the latter of which DOES need the Xenoblade Chronicles 2 game itself to use.