I think a vacuum bag is fine for short term storage such as for travel, but quilts need to breathe. Plastic doesn't allow for air circulation.
This summer we transported 75 fleece blankets in the car on a 2 day trip. They were prepped for my mom to make for Project Linus. With everything else we were taking, I don't think we could have gotten that fleece in the car without those "space saver" vacuum bags.