it was USED as such, but was NOT designed for such use. The fact it succeed so well at so many roles it was used for is a testament to how well it was built and designed.
As for the 28 air forces thing, it was used by ONLY 15 and only then if you count CAPTURED CRAFT!!! Curtis-brand fighters were used by 28 air forces, but the P-40 airframe series only equipped 15. Get yer facts straight!!!
And BEFORE everyone flames me with the images of that Kittyhawk with all the markings, observe the nose marking that says "5000th CURTIS Fighter" on the nose. if it was used by 28 nations there would be an average of only 490.6 of them in every nation, when the US had 1000 at home, and another 8000 spread across the world. Britain had 750 on record, BRAZIL had another 400, RUSSIA had (and redesigned) some 1400... start checking the numbers listed by the countries and do the math, people!
Oh wait. 90% of America CAN'T even READ, much less do ADDITION. MY BAD!