I'm really skeptical of the utility of purpose made euro/competitive lines. They really seem like a carry over from skirting competition rules that limit leader length and require fly lines to be used.
Furthermore, I've just never had any trouble using conventional lines with any tight line or euro style techniques, and yet have the versatility I'm used to when I need it. A modern 10' 4wt rod paired with a conventional 4wt line is a very versatile rig for fishing PA. In contrast, pairing a 2 or 3wt rod with one of the comp lines might make more sense as those rods are already less versatile.
Lastly, I'm not sure there is really any tangible difference between the fine diameter comp lines and the floating running lines available to anglers fishing two handed set ups. I know that some comp lines are advertised as to having a taper, but at some of the smaller diameters and weights available, I doubt it matters. Some of these lines are very close to being level lines.