I know and I have, but puppy pads still get wet and stay wet. These claim that if they potty, it absorbs quickly and the top layer stays dry. I'm actually more interested in using them for my dog, the cats manage to hold it for a long time. I wouldn't want my darlings to have to sit on wet tinkle for hours until we reached our destination.
I have Cat Paper to use in the carriers, but I also have little litter pans to use if they will need to spend any amount of time in their carriers. Of course the times I haven't used the litter pans are the times I wished I had.