On my recent European road trip I noticed that a couple of Mk5 GTI's on the autobahns, in bright sunny conditions, were using sidelights+fogs as 'daylight running lights' (drl's) and so I did the same. If you are travelling at a significantly faster speed than other traffic you need to be seen. Also you need to see those big RS4 Avants, Porsches etc bearing down on you fast when you are doing 130 mph! The new Audis, especially the A5 series, have fabulous LED drl's.
People in the UK seems to generally be against LED drl's but I see them as an excellent safety feature and they allow you to better judge the scale and therefore speed of the car in your rear view mirror because there is far less dazzle.
I spoke to Hella not that long ago because they produce an aftermarket replacement drl which fits the ordinairy Mk5 Golf's fogs position. But they don't fit the GTI - Duh! It's the faster Golfs that need them more!