A Microsoft staff published a paper titled “Why do Nigerian Scammers Say They are from Nigeria?”. Now, you can get some PhD academic doses about the 419ers in Nigeria.
Finally, this approach suggests an answer to the question in the title. Far-fetched tales of West African riches strike most as comical. Our analysis suggests that is an advantage to the attacker, not a disadvantage. Since his attack has a low density of victims the Nigerian scammer has an over-riding need to reduce false positives. By sending an email that repels all but the most gullible the scammer gets the most promising marks to self-select, and tilts the true to false positive ratio in his favor
Watch out, they will put the algorithm to detect such emails when you use hotmail!