It vacuum seals bags of liquid since it evacuates the air from the chamber, not the bag the liquid stays put, there is no sucking from the bag. Sauces, soups, stews, meat with brine in the bag etc. They are also typically duty rated for continuous use, they evacuate much more air and the bags are much cheaper since you don't need to have the embossed bags.So, what do chamber vacuum sealers do that is different that a Foodsaver ?
As I mentioned though, we used a food saver for a very long time and it's true, "where there is a will, there is a way" :) The cons of a chamber sealer are initial cost, size, and weight.