I suppose with the paucity of printed material on the subject and owing to the fact it was a standard piece of equipment on most AFV gun systems produced by the U.S., other than anecdotal stories about a few crews disabling it, not much thought was given as to its relative effectiveness; At least not until rather recently and by a diminishing number of people that have a interest in such matters. However, it is well to note that subsequent post war production continued its use in one form or another and is a precursor to the modern stabilized gun systems used by most if not all serious AFVs designed to kill other tanks. The ability of a gun to fire, recoil, go back into traction and automatically re-lay roughly on target in a very short order is a huge multiplier in a gun fight. Back in the day (prior to using the modern M1 series gun systems) we figured we had a 5-9 second jump on engaging T-10's & T-54/55's without an advanced stabilized gun system and about a 7-12 sec jump on T-62s and T-72's with their automatic loaders that would have to bring their guns back to approximately level to reload prior to re-laying on target. In 7-12 seconds we could put 2-3 rounds out, Steel-on-Target, where they may only be able to fire a single round (and that was physically humping 105mm rounds into the breach).
As for its effect in ASL, I suppose there's a game-mechanic factor involved, tweaking a bit this way and that for "game effect". AFV combat in ASL, though fun and often tense, is a mediocre attempt at reflecting armor vs armor engagements at best. Perhaps the lack of Gyros in most U.S. AFVs represents tactical employment of the vehicles as much as the use of Gyros, sighting equipment, etc. The Germans excelled at individual tactical employment of their assets, approaching or withdrawing on oblique facings, using short halt firing positions more effectively, and use of terrain more advantageously than their opponents, especially early in the war and with more experienced or better trained crews. As the war progressed the Allies would learn these lessons the hard way but new units were constantly being thrown into the fight and it takes a while to get your brain cavity adjusted to an actual combat environment (head has to get screwed on right). I think the few gyro'ed vehicles found in scenarios more than likely represent experienced crews properly using all the tools given them to gain an advantage. JMHO.