The word "stable" can have different meanings, e.g. stable behavior/stable interfaces. I am using arch/manjaro on my personal machine, but I installed Debian for some of my remote family members (who mostly just need firefox+libreoffice+vlc+cups) since this makes me confident that they can get periodic security updates and bugfixes all by themselves without needing my intervention (while rolling releases sometimes require some adjustments or troubleshooting e.g. on the config files, etc).