ShipStation Connect printers are only shareable if the printer is locally connected to the computer running ShipStation Connect. In business IT, local printers are rare. They are rare because they expensive to support. Nearly all printers from small business up to enterprise are IP printers. If a print server exists--as it does in all but the tiniest, unmanaged systems--they are shared through it.
Stamps.com Connect allows printers published through Connect to be used by any number of Stamps.com client computers whether it’s shared from a print server or by direct IP. ShipStation Connect should do the same.