Can a diaper keep you "twice as dry" ??

I Googled the phrase, which seems to be applied mostly to antiperspirants and other personal hygiene products.  "Dry" is pretty much an absolute term, so from a strictly grammatical standpoint, I don't think something can be "twice as dry" as something else.  "Half as wet" would be logical (and measureable), though clearly for advertising purposes, noone wants to tell the public their product will leave you half as wet as someone else's.

Perhaps I can understand it in meteorological terms, if someone says that a desert air with 10% humidity is "twice as dry" as air with 20% humidity, because both are "dry" compared to normal experiences.  But if I hang up a wet towel and check it a few hours later, I don't say it's twice as dry as it was earlier, because it wasn't dry at all at the reference point.  Same thing with a baby's diaper.

I'm not going to think about this any more.  Gotta move on.