There are no binary packages for Arm in our repos. I promise it didn’t run fine.
It mostly will work, but mail won’t, and jails won’t. If you don’t need mails and you don’t need jails, go for it.
If you need mail, you’ll need to configure it yourself. None of the Virtualmin user and domain related features will work though, because procmail has to be able to start as root and switch to the domain owner or user (that’s procmail-wrapper, a binary package that we provide that doesn’t exist for Arm, yet).