I use these in flightcases that come on the road with me, and where I soldered my own input and output panels. It protects the connectors from dust and bumps and scrapes, and adds some extra insulation to the back of your connector. While they probably aren't really necessary if you have done a decent soldering job, I do like the extra security they provide, especially since I mainly use them on flightcases with amps that run art installations and thus are not always under my own supervision.