Originally Posted by Turbotronic

You answered the question. There are a few preconditions for it to work well and consistently so. It is not fit and forget. Because you are aware of this and take the required precautions it works for you. Unfortunately there are others out there without that insight. Also Festo does not spec the leak rate for that fitting. All seals leak depending on medium and application.
These are really light and reliable. Easier to remove/fit than regular barbs but with lockable gland. Goes to zero Bar. The diff between zero and 0.05 is an airleak...