I've been doing a number of application discovery jobs on individual nodes, and I noticed that it would be a huge time-saver if I wasn't having to select/deselect specific credentials each time I'm doing a discovery.
In my particular instance, I may need different credentials if I'm doing a discovery on a windows node vs. a linux node. Similarly, nodes on my DMZ will not accept the same credentials as nodes on my primary network.
I realize that this is different in every organization, but I'm sure there are more than a few out there who would benefit from being able to group our stored credential data and then be able to select a specific group of credentials to apply to a node for discovery.