Those organizers act as air compressors though. So you can get a lot into them and then when you press and zip, you squeeze the extra air out. It otherwise meets the linear carryon requirements... and I guess you don't have to use all the cubes anyway. I just mostly like the chair thing.
I actually am not a big fan of cubie organizers; I like the compressor bags that you can throw clothing into and then roll up to squeeze out the extra air. They've always worked great for me. Plus, you can use the bags again once you're on your trip to keep your dirty clothes seperate from your clean ones. Plus about the cubes though is that youc an put your loose crap in them (deoderant, makeup, etc.).