Well we have a VAG car (not a Golf just yet, still waiting - but a MY19 Seat Ateca) - with normal LED headlights, and we do have headlight washers. They're reasonably effective - not to the point where i could not live without, but they certainly do the trick. I'm genuinely surprised by that. I don't think that weight savings play a role there, there's so much stuff where you could save (more) weight before you'd think of reducing liquid, but cost saving is probably spot on.
I don't think those 3-4kg in weight savings play a big role in emission levels especially on the GTE. I gain that (and more, sigh) over christmas alone.
Genuinely surprised, since we have it on a Seat, we kind of expected it to be on the Golf (at least the top end ones) too. The Tiguan (where saving weight would make more sense) has them too, so i'm pretty sure it's simply "cheaping out". Ah well. Obviously not a deal breaker, just surprised.