A sure sign of insanity. As a weapons system it would have proved absolutely worthless. First, it would be unable to move by road or cross major rivers as neither any road or bridge would support it. It likely could not have even operated on anything but hard ground. Moving near buildings would have very likely caused damage to them just from ground vibration.
Its enemies would have struck it with artillery and aircraft not to mention just shooting it up with vastly superior numbers of guns, tanks, and other systems that were produced in abundance.
It reminds me of an old science fiction board game called Ogre. One player had the "Ogre" this huge supposedly unstoppable tank-like vehicle. The other side had what one might call "conventional" tanks, artillery, etc. Against anyone but a complete fool the Ogre always lost.