Fair point. For desktop I don’t recommend them (in part for the reasons you suggest), but for mobile I find they work well as select UI for a long list is often better.

For most modern browsers it's not. The greater difficulty some users have in testing is with the appropriate choice of an element which represents navigation. A select element doesn't expose itself as clearly to screen readers to inform what links exist on the page.

"When navigating with a keyboard, merely browsing the options with the arrow keys can trigger the change." Is this still true? From my testing it appears not to be the case.