Listen to Davies Richards (Flare's designer/owner) he says it has a dual benefit and the two come hand in hand.
I think most people, when reading "minimise distortion" in relation to the Flares will be thinking of distortion in the sense of some noise on a waveform. The word distortion is wider than that and means anything diverging from the input signal.
In the Flare's case, the distortion they feel they've eliminated is the distortion caused by an asymetric movement of the diaphragm and this is also the very same type of distortion which can cause ear damage for lower volumes than should be the case with a symetric diaphram movement. Therefore cause of hearing damage (specifically too large a movement of the ear drum in one direction) is minimised inherently to the design/theory. It means you can play louder with the ear drum moving less because loudness is perceived by the whole pressure wave cycle and not perceived from half of it, if you see what I mean.
The Adel thing is different in that it appears to be about releasing net pressure in the ear canal when it goes over a mechanical threshold. It doesn't address asymetric movement of the diaphragm -> air -> ear drum. I think it is like when the sea rushes in and out of a shallow cave or cavity in rock, the air compresses and kind of explodes against the back wall of that cavity (a form of rock errosion). The air is pushed hard into the ear canal when playing loud and so the adel is supposed to lower the pressure in there, a pressure valve.
For me, the best general way to protect your ears is to turn the volume down and you can only do that when the isolation is very high - a good sealing tip pushed in well is good for this.