basically means feck all in a road going car. I'd hazard a guess that a good deal of enthusiasts pouring over the mass of their wheels could shed more weight from the vehicle by eating fewer pies if they're in search of performance gains 
....I don't agree. Although my car has done occasional trackdays I DO search for the apex of corners though always obeying the road markings and I DO have fun driving enthusiastically on the road when the conditions are safe enough to allow it.
You don't have to be driving at high mph speeds to have fun in a GTI.
The combination of lighter weight wheels and other handling mods significantly and noticably increase the feedback and make a GTI more tactile to drive. Alloys like the OZ Alleggerita's also better accommodate bigger brakes and deliver better brake ventilation.
What you are saying about tubby pie eaters has some relevance but is far more relevant to sport such as riding uphill on pedal bikes. IIRC my race bike only weighed 17lbs but I weighed nearly 11 stone even when race fit.
