It does look cool.@Blades:
There are two main reasons (that I am aware of ) for installing aftermarket barrels:
1. To be able to shoot bare lead ammo
2. To be able to interchange calibers
Another possible reason: it looks so danged COOL!
(*PS* Don't have them on mine...no point in a G26, and my G30, well, haven't even started to tinker with her!)