It is rather counter-intuitive to think adding more cases into a suitcase would make packing easier.  But these pack-it folders and sacs do help.  The only improvement I can think of is lighter material.  They are thin (durable) nylon material but still add weight.  Additional benefit is purely psychological.  Having been subjected to allegedly random search at various airports, I feel a little more relieve to know all my underwear won't be strewn about when I open my luggage.