It's the default for buttons inside forms, but it's SO trivial to add type="button" than any argument that div's are a better choice because of this should be dismissed as unserious trolling out-of-hand.

Nope, it's the default:

https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/...

Maybe you’re thinking of <input type=“button”>, which doesn’t submit?

I seem to recall that once upon a time the default type for a button was in fact "button" but at some point (somewhere in the region of html 5 / es6) it was switched into "submit".