Yes, Viper Backup can backup SQL databases, However:
Viper Online Backup recommends using SQL Server Management Studio for Full or Differential backups of SQL databases.
The SQL backup file(s) should be saved to a local folder on your server or another network location. Viper Online Backup will backup the SQL Backup File daily. If you are not concerned about a transactional based SQL Backup with Logs, you can simply use the Viper Online Backup Client to backup a SQL database (VSS is used in the background with Viper).
Using Viper Online Backup to backup an SQL database directly will only create a copy. The Viper Online Backup Client will not truncate SQL Logs. To address the concern with the Viper Client running up a new backup of the SQL Database file daily: Viper will only backup the Delta to each SQL backup file. The same would apply when only using the Viper Online Backup Client to backup the SQL database directly. Viper will backup the Delta changes only.
When there is a need to recover an SQL Database, you can simply use Viper to recover the applicable SQL Backup File reverting back to any date and time when a backup was run. After recovering the SQL Backup File from the Viper Online Backup system, you can open the SQL Server Management Studio and recover the applicable SQL database. If you decided to only use the Viper Client to backup SQL, you would restore the copy of the SQL database from the Viper Online Backup System, then replace and overwrite the existing SQL database.