I doubt anyone (on CCR) is "continually" monitoring their gas. But, I do check mine usually a couple of times during a dive. It's peace of mind that I don't have some leak that I didn't realize I had.
A reasonable answer. I can see the benefit of that.
If you don't need to check your dil and O2 pressures during the dive, then you don't need AI or even SPGs, right?
No, that's not what I said. You need to check if you have a boom. Or if you do something unplanned, and use a lot more gas than anticipated.
So I have that capacity with SPGs, but it's so rare that I don't need to go out of my way in terms of cost, clutter and screen real estate to make that data so readily available. If I have a boom, I grab my SPG and look at it. Otherwise, it stays out of the way.
Why not check your dil and O2 cylinder pressures just before you install the cylinders on your CCR, using a separate pressure checker? Thus eliminating the potential failure points associated with the HP hose, SPG, et.?
Some people do this - button gagues on the first stages that you check only before donning the rig. While I don't do that myself, I can see the argument for it. You can tell that you are completely OUT of O2 or Dil without a gague, right? And whether you have a gauge telling you have no O2 or if you just can't keep your PO2 up, you are going to do the same thing, right? Of course, once you have checked that it's not just a valve rolloff...
So the question is not about being out of gas, but how will watching your dropping O2 or dil help you? Are you going to run your dive by watching how much gas you have left? That's OK if you are, it's just a very different type of CCR dive planning than what I'm used to.
If you do need SPGs, then why not have them showing on your computer display instead of having to look at physical gauges?
Because of the reasons I outlined in my post.
As I think I posted before, I have appreciated being able to look at my gas consumption data after a dive, to see where during the dive I used my dil. When I can see that I used dil at the very beginning, up until I got to my max depth, and then I used no more during the rest of the dive, then I know I've done well. If I see that I occasionally used some more after getting to max depth, then I know I need to review what I was doing and figure out if I can do better. Was my mask leaking, causing me to need to clear it and waste dil? Or was it just that I was doing some up and down stuff on the bottom? Or something else?
OK, but I kind of know when I'm losing dil because of mask clearing or a lot of up and down. But I see your point. Not enough to change the awesome JJ design, though!