Storing credit card data has its own set of strict security rules that need to be followed. It’s also the credit card company’s problem, not yours, as long as you dispute any fraudulent charges early enough.
I’m coming at this from the perspective of a developer. A user can always use a longer password (and you should), but it’s technically possible to make an 8 character password secure, thus the NIST recommend minimum.
Yeah, multiple languages or even putting an ê or something in an English password to mix things up. It makes perfect sense to allow.
It’s a good thing they require each codepoint to be treated as one character for the length limit, since “🤔🤣” is 8 bytes on its own, but the unicode prefix is trivial to guess.