I am still using my original roll a cot purchased many decades ago and used a bunch. Some of the velcro has unraveled but that is the only damage, still works like new. But, I have always placed the cot in a properly sized dry bag. Not sure if this setup floats but it has kept the cot dry and protects other gear from the roll a cot frame..
on the other hand, due to the mesh construction, if a person just tossed a roll a cot into a big mesh gear bag, my bet is the cot would dry fast even if the boat happened to flip.