Using an inferior, underpowered unit isn't going to help. The Ural Bomber prototypes were unusable in combat, so wasting limited resources on producing them is going to hurt general rearmament, which is exactly why Wever shit-canned them for better designs in the future once German aviation designs improved.
In a world of infinite resources, maybe. But Germany in 1936 had limited aluminum and could not waste it on an inferior model when the future could produce an actual combat-worthy design. In fact starting over after producing the Do-19 or Ju-89 (the better of the two BTW) would be far more costly and not really advance doctrine or knowledge all that much, as German air and ground crews would have to relearn everything on new models, not to mention production facilities that would have to retool, retrain, and relearn how to produce a new unit. If Germany were the US it could afford to do that, but this is 1930's Germany that has to make do and only produce units that could be competitive. As it was neither model lived up remotely to design specs. All that could be gained from them was the experience of what NOT to in designing them. In fact, just accepting the prototypes and working them over for ideas was the best that could be made of the designs.
I heavily disagree with this. Germany had other options in 1940, such as masses of proven medium bombers. The problem was the Britain could not be defeated by strategic bombing, nor could Germany afford the investments that the US and Britain made in that arena (during the war to boot, not prewar). Instead Britain was much more vulnerable at sea, thanks to her island status requiring vast imports to defend herself, let alone take the offensive. Instead of investing in techniques, technologies, and numbers of useful aircraft for naval blockading Britain, it lost the ability to force Britain to the table.
Instead, just as Wever and his staff envisioned, the heavy bomber was for use against the SOVIETS! In 1941 and beyond is where the 4-engine bomber is actually useful. The Moscow Oblast has massive amounts of vulnerable industry (forget the Ural industries, targeting would be a nightmare), which OTL were never even targeted. Hell, go after Baku and disrupt Soviet oil production, again something never attempted. There were reasons beyond just the lack of a suitable bomber, including Goering's shitty leadership and a string of terrible CoS's of the Luftwaffe.
Also part of the reason Wever pushed off production is that he didn't expect war before 1943 and thought he had time before the war to prepare. No one expected war that early. But assuming 1940 is when serial production ramps up, Hitler started the war just about the time to take advantage of the new bombers. Obviously they wouldn't really become truly effective until 1942 by which time they would have had more experience using the weapon, but still its a hell of a lot better than OTL where the Soviet industry was left untouched.