I use them as a 'Cancel' button. If I missed my menu item, it's usually quicker to stop at the next '--', wait for it to time out & start over. On rare occasion, I'll go into the menu by accident as well... usually when I'm concentrating on something else, or if I didn't press the button fully & the circuit registers breaks in my press... and they time out a lot faster than waiting for a menu item to show the setting & then time out.
I don't know why they're there, but that's how I use them. I'm not aware of ever hearing an official answer.
The 'complaints' about endless clicking come from non-owners/non-users 99% of the time. Once you actually use one for a week or 2, you find that using the menu really isn't tedious as some of the General Forum
threads would have you believe. I'll admit that it was one of the biggest hangups in deciding to
buy my first one. When I got it, it didn't take long to realize it's a complete non-issue. The other 1% are the impatient people who like to click the menu all the way around when they miss their setting... and miss that same setting again.