> Besides that, is there any other advantage of gbak or nbackup
> against an ordinary copy of the database?

When a GBAK backup finishes successfully you know that your database
is physically intact. When a restore finishes successfully you also
know that your database is logically intact (consistent).

As you mentioned, running a GBAK or NBACKUP backup doesn't require you
to shutdown the database. You may find some time to do that now but
maybe in a few years your users won't be happy anymore that there is a
service outage once a day.

A GBAK backup does a garbage collection on the database (unless you
use the -g switch).


Best Regards

Stefan