why Sperry made an instrument that displayed the reverse of all other AH
I opine that was in an era when there was little standardization. Skilled instrument pilots had mastered flying in IMC with less, and a confusing (to us) presentation was only a small factor in their instrument flying, where a newer pilot perhaps depended too much upon a single instrument.
I once punched into a line of snow, straight, and level, lots of altitude, everything normal. Moments later my attitude indicator showed me in a descending roll. It even had a vacuum warning flag (which was not presented) giving more reason to not suspect an error with its indication. I began to follow it for a moment, but realized everything else was normal, only it was presenting conflicting information. So I reverted to needle, ball and airspeed, along with confirming VSI and altitude. When I emerged from the line of snow a minute later, I was straight and level, and everything was correct, other than the attitude indicator, which was pretty well upside down. Its gyro had chosen that moment to seize a bearing. The instrument did not know that I had suddenly entered IMC, just a one in a million coincidence.
Cockpit standardization is newer than some of the planes still in service. With 60 hours flying a mid age DHC Beaver last spring, I was asked to ferry back another. It was more than 600 serial numbers older, and its very much not not standard to the one I had been flying. Instrument faces were different (so different presentation) and the throttle and propeller controls were reversed. It was fine, as long as I thought about what I was doing.
There can be a lot of "can do" pressure, particularly piloting the fancy plane with the important passengers. Newer pilots have to learn to step back and recognize a situation with increased risk and pressure, and take more time, or consider declining.