I have moved my wife to a button SPG to validate the transmitter as functional before going into the water and also at least some sort of a backup if the transmitter fails during a dive.
I used to have that same setup on my doubles regs. Then I was diving one day and a well-known, highly-respected (including by me!) GUE instructor was there and he was looking at my rig. In doubles, the regs are general sideways(-ish), so the button gauge was on the side pointing up. It was small. Nevertheless, he looked at it and said, "you don't feel like that's a bit of a snag hazard?" I thought about it, and decided he was right.
Plus, having it there meant that I could assemble my rig, turn on my gas, and do a basic sanity check to confirm that my tanks were full without having to find my computer and turn it on. Eventually, I realized that that meant I was creating the opportunity for myself to find out much too late that I either forgot to bring my computer, that the computer was dead, or that the transmitter was dead.
So, between those two things I took the button gauge off. Now, I am forced to find my computer and get it out to check my gas when I assemble my unit. Less convenient, but a better process, I think. Especially when I'm assembling my rig on a boat that is about to head way out offshore. Being forced to make sure I actually HAVE my computer, it is not dead, and the AI transmitter is not dead - all while the boat is still at the dock - seems like a good idea....
If I just need to check the pressure in a tank, I have a separate tank pressure checker gauge for that. No need to dig out a reg set and computer.