Sats are the standard. How long until people will use it as UoA? That depends how long people are willing to be pegged to dollar. It's all about changing the mentality and use exclusively bitcoin. Bitrefill is a good service but that doesn't mean you live in a bitcoin standard, is still pegged to fiat.

STOP using fiat and most importantly stop borrowing fiat. Every fucking time you request more fiat you are creating more and support it. Every fucking time you are "charging" a visa card by selling your sats, you are creating more fiat. You are part of the problem not fixing it.