+1 for backup on login feature - noted
does Veeam also count "Backup storage attach" when logging in?
No, it should not. You need to physically attach USB storage to PC so the backup is triggered by special even in the OS.
"At backup storage attach" does not really work reliably for my NAS
If you mean NAS target as a shared folder, then yes – in the BETA this option works for the USB devices only. However we have some plans for improving this functionality in GA