Your described thinking pattern does not apply to 95%+ users, and might add confusion leading to retention loss (e.g. 2 text boxes? Wtf, two boxes? What do i type in the second one? Whatever i’ll switch to the usual). Every project with at least 100K non-tech users I’ve worked on, has shown that sort of thinking just doesn’t translate.

And regarding “average doesn’t exist” - that’s true. But no company does a/b testing to land on average. I’d assume a good 85%-kinda pass rate for these type of experiments.

I think A/B testing may have value in selecting a specific path preferred by 85% of users, but it seems like alienating the remaining 15% doesn't feel great.

95% of users might not want the double-textbox, but 5% might, and some might want to use it someday.

I think, make enough of these decisions, and there's bound to be mounting friction for users with different preferences navigating your app.

Ideally, the app should offer a way for the user to intuitively configure the app to their own liking.