This.
You install a virus scanner on your smb fileshare or your mail server, for instance, and pipe attachments through it to protect windows boxes. That's the only sensible use.
Yet, idiots make policies like "all servers must have AV installed for safety" and thus some shit app sucks down all the CPU time and scans memory (ohai PCI compliance) just because the CTO doesn't know what 'less' does.