Arch is bleeding edge though. Debian is known for it's legendary stability. (along with most things in its repos being super old) Wouldn't that mean Debian in most cases is a better choice for a server than Arch?
Arch is not "bleeding edge." Bleeding edge means the most recent possible update, regardless of stability. Arch keeps as up to date as possible with
official, stable releases. Unless you edit
pacman.conf and enable the community-testing repo, Arch will never update to a bleeding edge build of anything with
pacman. The AUR may contain bleeding edge releases, but they are unofficially supported so they can hardly be considered part of Arch. This may break your current configuration, for example a
lot of packages depend on builds of Python 2, but Pacman will download Python 3. This may be undesirable, in which case you can pass on the Python 3 build and download the
python2 package. You won't be able to run both at once without some configuration, but it'd be the same way on Debian.