Agreed. If the Germans had recognized the need for a longer range capability for the Bf-109 during its design, the tanks (along with the Bf-109G, with its greater internal fuel vs the Bf-109E) would have been ready for the BoB, making the fragile A6M unnecessary.
The dual tank option is even better, likely giving well over 2,000 km range, for more than six hours endurance, including combat time.
I wonder the the aircraft could takeoff with all THREE drop tanks, like this P-40 below.
With the G's greater internal fuel, three drop tanks, the right prop and engine settings our Bf-109G could likely fly from Calais to John o' Groats and back with fuel to spare.