The Paradigm mid-tweeter driver does use a more capable material, but implementation matters as much, if not more, than simply choice of the material.
In high frequency driver use, due to its very high self damping (not internal damping), ultrasonic breakup is pushed up fairly high for a 25mm dome. Down at the bottom of the band, it might reduce distortion if a designer chose to use first or second order crossovers and a low point, but that isn't the case here. Paradigm uses third order all around and the tweeter is crossed at 2.4khz.
The mid driver on the other hand is on the larger side, which does begin to beam at just under 2khz. I'm assuming the lens placed on the driver assists on the integration, but well have to see measurements to know. In any respects, the material would push its resonance up a bit further, which aids in keeping its distortion in check since Be doesn't have very good internal damping properties. The larger radiation area would also allow greater dynamics in the range with less motion and thus distortion.
While you may read that it reflects poorly on the Dynaudio, it doesn't. The materials chosen by them have much better internal damping, which simply means some of the breakup energy is absorbed by the cone material.
Think of it like suspension in a car. In Paradigm's case, its a sports car with a very stiff suspension. It requires a smooth road to operate at its best (avoiding distortion). The Dynaudio has a more compliant suspension and can deal with a little imperfection without disturbing the ride too much. Consider the road condition as simply distortion and not musical signal. Paradigm, had to ensure its drivers worked specifically in their operting range, which is fairly broad due to material choices. Dynaudio could accept a small bit without it all falling apart.
But as long as the designers keep the drivers within their optimal range, a competent design can be made with either. Each material just comes with its own properties you need to contend with.
