A problem with many of those is that they are not quick release.
Real estate on the waist strap is an issue. By the time people of NORMAL dimensions snug the strap up, there is no room for anything. The DR pockets are quite large and especially if set lengthwise will stick out a little. They do with me, my waist is 31 inches. As a bench mark, I can carry a knife and the DR pockets and nothing else. With the (2)XS QR pockets I can slip another item in there, maybe. My can light (can lights are obsolete for open water/night) is not mounted on my waist, it goes in a purpose made pouch on the lower cam band on the opposite side of my XS trim pouch.
Another good thing about distributing weight is that if some of it dumps accidentally you do not go dangerously positive. Keep in mind, I am assuming you are diving wet. If she is dry then I will leave it to folks who dive dry more often than me to advise.
N