Helps preserve

For the maintenance of nubuck shoes it is ok. It applies well. I applied two to three coats. No need to spread with a cloth. Dries quickly. Gives medium water repellency. Not very efficient.

It can be

It doesn't seem very efficient, but it applies well and actually waterproofs.
When lightly soiled, it is enough to wipe the boots with a damp cloth, but after such a solid trek in bad conditions, I don't think there are any strong impregnants or gore tex ;-)