I'm talking about a fabric. Not cigar tobacco from an island nation blush

One luxury item I really enjoy is my Montbell inflatable pillow. Comfortable and light, but it serves no other purpose. Recently I have stumbled upon cuben fiber drybags like this one and similar. I was thinking that bonded seams, a non porous fabric and a tightly rolled closure may allow such bags to hold air all night. One of these could keep my sleeping bag dry and possibly allow me to leave the Montbell pillow at home.

Has anyone tried this? Yes, I realize that what amounts to a plastic bag filled with air is not the most comfortable pillow and I may be giving up a little comfort over the Montbell but I love the dual use idea.
If you only travel on sunny days you will never reach your destination.*

* May not apply at certain latitudes in Canada and elsewhere.