The trouble with partial panel is that students get a false sense of how easy it is during training. But they know it is coming and they are the sharpest they will ever be at flying the gauges. The real world scenario is you are flying along fat dumb and happy years later and the vacuum pump or the AI itself fails without you noticing. Then you start following the toppling horizon and now you are in an unusual attitude with the T and B saying different things. Sadly the accident record paints a not very pretty picture of what happens next
Anybody who flies any kind of hard IFR without a back up independent AI is IMO foolish.