What is SmartCAT "Shared Port" used for?

The "SHARED" ports are just virtual cable pairs and, once created, do not depend on CAT or the radio. You can use them, for instance, with DDUtil, to connect between programs. The "shared" ports are always available, regardless if CAT is running or not. For explanation and more details regarding SmartSDR CAT; are available in the manual.

I did and I makes it a lot easier to configure than running VSPManager. by the way if you are going to remove VSPM, please make sure to the delete all their virtual com port first ... Again do not delete VSPM from control panel until you delete all the ports. Otherwise, you will end up like me spending a lot of time trying to delete them from device manager!