I have a cargo pouch sewn on my drysuit leg, in which I keep my surface marker buoy, my 150 ft spool, and my back-up mask. I have not yet sewn cargo pockets onto my wetsuits as well, but I plan to do so soon, before my next warm water dive trip. These make other pouches such as on vests or B/Cs unnecessary.
I have 4 D-rings on my hog (Hogarthian) harness, and one D-ring on the front of my crotch strap.
I use the D-ring on my crotch strap to attach to my diver propulsion vehicle (scooter) so that it can pull me, rather than straining my arms as with some other models.
My right shoulder-strap D-ring holds the bulb portion of my cannister light with a bolt snap. Or I can use it for my second deco bottle whenever I have 2 such bottles with me.
My left shoulder-strap D-ring holds my fist deco bottle OR my submersible pressure gauge attached to a bolt snap.
My two hip D-rings each is the end connection for my two deco bottles. If I am not wearing deco bottles, then these are usually empty.
The left side D-rings are also where I will clip my submersible pressure gauge as well. If I am diving with twin tanks, I clip the SPG to the left hip D-ring. However if I am diving with one tank, I clip it to the left shoulder D-ring. The reason is that a twin-tank dive is guided more by your timer/clock, whereas a single tank dive is guided more by your SPG, and it is easier to see and monitor when connected to your left shoulder strap than when connected to your left hip D-ring.
Those are my thoughts on pouches and D-rings.
As PACO earlier said, naval/military divers do not have the same needs or uses for pouches or D-rings. They are not out taking photos or riding around with DPVs enjoying the undersea scenery. They are instead advancing along an azimuth of attack with the water as their avenue of approach to ambush and destroy an enemy target. If they deployed an SMB or shined a light, this would give their position away. And if they used open circuit scuba rather than rebreathers, this would also give their position away. Totally different thing altogether.
Conversely, naval/military gear would be unsuitable for civilian sport diving purposes as well.