...you can copy the catalogs elsewhere before deleting them manually. This just means that if you want to restore data from a tape with a deleted catalog, that you either need to copy it back to the Catalogs folder, or recatalog the tape.
Making that change suggested though only affects catalogs going forward...it is not a retrospective change (ie. doesn't delete old existing catalog files).
Beware that joblogs and catalogs are two different things. Joblogs contains information regarding how the job was run, status, error messages, etc. Catalogs contains information about the backup set, what resources are backed up, etc.
The joblogs cannot be archived or exported. However, you can change the path where the joblogs are stored. See this document