Difference is, on Debian you can leave machine without updates for few months, while on arch you will have troubles if you don’t update for a week, also if you install Linux for your relative, it’s better to do debian based distro because of this update cycle since normies don’t update their machines every other day, source: I’m daily driving Linux for 9 years on all my machines and some of them lay around untouched for months, also installed mint on relatives PCs