Yes, but there is a thing what many comments here misses: those email do work, so not only they filter out not-dumb people, they are running on a successful strategy.

Using a proper spelling would improve the conversion but also would add a lot more work for the scammer and therefore he can miss a real doofus who can be scammed, so the overall KPI (heh) would be lower.

Yes, it still the same, but with an additional key part.