Anybody who needs to know this detail to design or repair a device, already knows it. There are no simple enough devices where this is relevant for casual repair or modification. You can fix your DC devices such as cellphones and your AC appliances such as refrigerators, and even design your own phones and refrigerators, without knowing in which direction the fundamental particles flow.

Could you give one example

In terms of pedagogy, it is a problem.

I started tutoring other kids in grade school and eventually got paid for it as a side gig later in life. If I ended up covering electronics and/or general electricity, I saw the same thing I saw as an undergrad taking EE courses: confusion. A lot of people found the situation counter-intuitive. It required extra mental labor for them. Hence, multiplied against millions of people, there's overall lost time.

And this isn't just in young people, either. Knew a guy who swore up and down that the "electron holes" really represent positrons.

Bad notation, weird syntax, poor choices in variable names, and so on, all of these are a collective drag which could be streamlined away.

Seems a pretty trivial change, like, hot water's on the left tap not the right tap.

Humans are more than capable of handling that minor conceptual change. Life routinely throws far more challenging changes to adopt to.

Nothing fundamentally changes because of Franklin's incorrect guess. The postit sticker goes "there " instead of "here" kind of a thing.

Certainly not as grandiose and melodramatic as putting humanity back by a decade.

It didn’t