Doesn't the disconnect itself act as the 'disconnect'? I mean, you take the disconnect off of the keg so why would you ever need to take the hose off of the disconnect via MFL quick fitting? I am more concerned that this is yet another component requiring a good seal and possibly an o-ring which adds another point of failure.
Easier to clean the inside of lines, for one. Another thing is being able to use those disconnects for different length line... which isn't as easy to do with barbed disconnects since the lines end up pretty stuck on there.