en.worldtempus.com
"A particularly hard white gold alloy is accordingly used in this escapement assembly for the pallet fork and the escape wheel."
But it doesn't sound like they do it because it's a good material, but because they just toss the whole escapement when they service:
"watches of the new era have all been equipped with the interchangeable escapement assembly and the pallet forks and escapement wheels are once again being manufactured in gold."
To me, that's another reason I will add to my existing list for avoiding one... What if Moser wasn't around or they stopped making the replacement escapement? Your watch would be toast. I don't see an advantage to using gold here. It doesn't add to the looks, but likely reduces longevity and makes service forced through the manufacturer because the escapement is entirely replaced, not repaired.
Unless I am missing something?