Like Chris and Russel, I don't see any CONS to add the target to SCC, on the contrary.
(But I don't see the PROS to add the workspace)
There is a :
"scc get latest version filelist" bullet in the doc, but it says that it's not for PBL unfortunately (never tried it)
So I feel the only command to get latest version is "scc refresh target".
Maybe your SCC has an API to do it without Orca ?
IMHO, OrcaScript needs some enhancements, for example I didn't find a way to specify the manifest that you can define on the project painter.
I never understood the "importonly" option by the way.
Regards
Guillaume