In reply to Paweł Bystrzan.

Thanks for your feedback! -- I know that.
What I meant is: change an option that is for the backend but for some reason is only accessable within the Customizer. To set it I have to:
1. open Customizer
2. open a panel in Customizer
3. find the option there, set it/ tweak it
4. wait for the live preview --- if is any regarding that option...
5. save and waiting for the go back.

Makes 5 steps/ clicks, including some moments of waiting time...

Otherwise - when I'm already in the backend, it's fewer steps:
1. open specific admin page
2. set option there
3. save.

From there you can go to other options pages or whatever.

2 steps saved.

May sound trivial, but if you work hours and hours in the backend each day, then IT DOES MATTER!

Customizer has to be choosed wisely by developers if it really makes sense!