"If people in the U.S. aren’t suspicious of free money, PayPal payments that look fake, the absence of a payment in their account, fake emails from PayPal’s FBI department or just Nigerians in general, then they deserve to have their money taken from them." I could easily see my parents falling for this. I don't think they deserve to have their money taken. Although, to be fair, I doubt my parents could set up and us…
God help us if the scammers ever find someone who can write correct English. I know many people get caught by these scams, and I suspect that the numbers would increase if the wording was improved a bit. There's a metaphor about conversions and copy-writing and startups in there somewhere.
By peppering the letters with bad spelling, punctuation and case mistakes, they eliminate 99.5% of the population who correctly detect it as a scam. Thus, when they do get a response, the person is much more likely to convert.
It applies to startups if signing up the customer requires cost on the part of the startup. If, for whatever reason, you had to sign up a limited number of people and invest time in each of those people, then reducing your response rate by, say, making the signup process complicated, would allow you to pre-qualify your audience by those actually able to navigate their way through it.
It would have real applicability if you wanted to get a limited market for beta testing.