A shareport is not a bad idea, but it only allows 1 user at a time which defeats the one purpose. For example with a printer. I print, while my wife waits upstairs for me to finish and then she prints. it would almost save more time for here to transfer the print document to my PC and print everything from the one PC. And in that case the Printer can be connected directly to the 1 PC, so why a shareport?
As gunrunnerjohn pointed out - the shareport allows for a printer to be shared automatically - but even if that were not so, using the shareport to manually select & deselect which computer is connected to the printer is quicker and more convenient than transferring the file or physically disconnecting & reconnecting the printer.
In the case of a physical disconnect/reconnect - someone is going to have to get up out of their chair and move the printer from one location to another - I don't think there is going to be any debate on time & effort saved there - so let's look at transferring the document.
You're in the middle of doing whatever you're doing - surfing the net - and she calls you and says "Honey, print this for me" and you have to stop what you're doing, open up Word or whatever and print it - and then go back to what you were doing.
There is a whole market segment built around printservers - just to make that particular interruption go away.