Frankly, anybody who can't handle changing from QNH to QFE and back again during a MATZ transit, or just the once when arriving at an airfield, probably lacks the mental capacity to be safe in charge of an aeroplane. Ditto in a QNH only environment mentally subtracting airfield elevation from the altimeter reading.
Frankly, I don't get the fuss. Using QFE is easy. Not using QFE is easy. Switching between systems is easy.
G