Bitcoin has had mBTC. And μBTC, more commonly known as bits, though both of these have somewhat fallen by the wayside as sats became valuable enough to be talked about themselves.
I'm not going to worry about what people who've barely heard of Bitcoin haven't heard about within Bitcoin. Especially when the idea of telling them that Bitcoin is worth 0.09 cents is probably the most confusing thing you can say to them given that they thought it was worth over $100,000.
And yes, I've had to have that discussion with someone who was dealing with an application that used this confusing notation, and it definitely added confusion to his onboarding.
