Sure thing.
So you have a beer fermenting in some sort of pressurized fermenter, mines a keg. Hook up a gas disconnect to another pressurizable container, then use the spunding valve on the container to capture c02.
Could be a keg, mini keg, paintball c02 tank, or even a 2L bottle if you want.
To serve/force carbonate, you use the c02 capture vessel with the in line regulator.
Say the capture container was spunding to 30 psi, you can use the regulator to bring that down to 12 psi and use it to serve and not have to bring your c02 tank, and regulator out of the kegerator.
Or you could use it as a dedicated for force carbing, or really any way you would want to use c02.