If the game took longer to reach moscow (more than 8 turns or so) it would be worth it.
The problem here is simply the fact that it doesn’t pay for it’s self for the resources needed.
For this example a lot of stuff is assumed.
You will probably need to take an artillary and man off of north italy (kill the malta fighter) which costs 7 ipc’s. The next turn you are lucky if you can get egypt (Doubltful you will since the uk can block with the fleet. Assuming this, we will suppose you can take egypt the next turn. Great, you get 1 ipc, the allies 12. This money goes into effect turn 4. The next turn you take syria also. ok, +2 more (allies -2) Total gain 7 ipc’s. Now it’s turn 5, you have +7 from oil, but subtract the 7 for forces needed, for all your efforts you have gained nothing so far, and you don’t get the benefit of killing the destroyer with the fleet (50% you lose a sub) More importantly, you don’t get to move the fleet to the atlantic to harass the allies. The second hit on your battleship can only be used once. It’s turn 5 and you have nothing yet from all of it, and you didn’t get to transport stuff on africa to europe (a valuable move to maximize tank output in later turns) So you don’t really get ahead until turn 6 when you should be taking moscow, or about to take it. You also lose valuable moves.
Another thing, the money the allies had to pay comes from usa. In my opinion the usa’s cash isn’t worth as much as germany’s. Therefore, overall it’s a waste. The only good thing, is you kill a fighter. The bad thing is the allies have an easier time landing in france, and to kill the destroyer in strait of gibraltar, you send a sub (you can’t take a convoy worth 3 now) So, the allies gain 3 ipc’s early on. Cash early is worth more than cash later… there are other reasons too, like the men taken from europe early on can’t pressure russia to trade belorussia in the mid-game which is important.