Not a blunder, just a very specialised tool with a very niche purpose of “being the tip of the spear in a setpiece assault on a heavily fortified strongpoint”. Now, them trying to convert their entire tank force to heavy tanks, that a different issue.
I still think heavy tanks were largely a blunder due to how expensive building them was, and how difficult it was to transport, tow and repair them.
They were so heavy their engines were constantly giving out and they were dead in the water.
Not a blunder, just a very specialised tool with a very niche purpose of “being the tip of the spear in a setpiece assault on a heavily fortified strongpoint”. Now, them trying to convert their entire tank force to heavy tanks, that a different issue.