What portion of the global population uses bitcoin, and is familiar with the word "sat"? 1%? 0.001%? Whatever it is, that is the extent to which "sat" is established. Explaining what "sats" means to people who are new to Bitcoin, or even those who are not new to Bitcoin but are unfamiliar with "sat", is a tedious exercise, often met with confusion. It is not intuitive for them, nor easy to remember. If we just call the units bitcoins, that problem goes away; there would be nothing extra to remember. It is a lower cognitive load for new users. It also removes the "I can't afford a bitcoin" unit bias that a surprising number of people have.

A large portion of the population is already familiar with bitcoin and its price in dollar terms. Suddenly shrinking that by a hundred-million-fold is going to be nothing but confusing. "Yeah, you saw bitcoin was $100k each last week, but now it's just a tenth of a cent. No, no, it's not because there was a price crash, it's just because we changed the definition, you see." By contrast, saying, "just like there are 100 cents to a dollar, there are 100 million sats to a bitcoin, so it's usually more convenient to talk about sats than bitcoin," is not at all something I've ever had difficulty getting across to people in my 10 years of using and explaining bitcoin.