I think they are better than nothing (and they might be near enough your only choice on some bikes) but they are not brilliant for the reasons Colin describes.
No safety clips, no mudflap, big gaps that let the rubbish through, only one front stay, and the fit of the rear guard varies with frame size, because the seat stays are set at different angles.
In any event the front mech and BB area see all the road crud, because the mudguard stops short, showering crud all over the transmission too I guess.
For discussions about bikes and equipment.
Colin.. all the bikes that i have with guards have the breakout stay holders fitted, i 'm a bit pedantic about guards fitting, so i rubber mount nearly every part ,i don't like rattles or noise or any antics with guards when i'm on the road.. On another note, early summer this year i owned for a short time only a defy alloy 2014 frame and it had great clearance for my big Michelin pro 3 25's [more like a 28 in section] and i could have fitted the type specific guards and been happy with the clearance, so i reckon whomever fitted the ones you witnessed hadn't maxed the height at the fork or rear bridges, or stays correctly.. although i agree with all you say, the modern cyclist, and purveyors of such machinery, are more concerned with the form than the function.. will
I like the vertical dropouts and have them on both my bikes, BUT, back in the day my first real bike was a Claud Butler Cordon Bleu. 531 double butted tubes, stays and blades,Nervex lugs and, most important - Campagnolo dropouts! How I loved those little screws to position the axle, I used to spit at the sight of naked rear dropouts..... 'spose that's quite sad really