Although, as I've said before, the vacuum thing is NOT intended for travelling, unless you have a very small suitcase, the bags will essentially enable you to easily surpass the weight limit for one suitcase on the airline (if you are flying).
If you aren't flying, and don't mind the potential stress of not having a vacuum available at the moment that you are packing, by all means, go for it!
Alaska / RCL Vision of the Seas, May '98
Mediterranean / RCL Legend of the Seas, July '00
Caribbean / Celebrity Infinity, Nov. '00
Transatlantic / Pacific Princess Final Voyage, Oct. '01
Caribbean / RCL Adventure of the Seas, July '03
Caribbean / NCL Sky, June '04
Caribbean / Celebrity Horizon, Dec. '04