Nashorn Factoid!!!
I think the proper context to view the vehicle is that it was an early attempt to provide the gun a PS mounting to giv eit some mobility. The Pak 43 is a great gun, but not so great if it is in a towed mount. Really, the gun is great but too easy to negate by artillery fire or simply avoiding. If you put it in an armored platform, evne one that is not very good in an absolute sense, it is still a useful weapon. That is not to say that the Nashorn is the mount of choice, but it is an effective wepaon when used correctly. You can make the same argument of the Elefant. Horrible weapon when used incorrectly, but they racked up good kills on the eastern front when they could sit back and use that big gun at long range.