[DSK]

Main reason why modern stuff doesn't have them is that would actually cost more than 10p to make it and new cars are made seriously cheap and generally a sprayer system alone is cheaper.

Usually anything with a decent lighting system usually needs a headlamp wash system of some sort.

I know mine is very useful during winter especially, seeing the car covered in snowy mush and your can see the clean sections of the headlamps where the wash and wipers did their job ensuring the light from the get gets out onto the road and not covered in crap.