> There's the theory that misspellings in a Nigerian email are meant to filter only the truly gullible, but IDK if that is true.

I think the crazier misspellings with wild character substitutions only started after bayesian spam filtering.

in this case is laziness another word for efficiency?

lazyness of the people trying to stop those scams should amaze you.

Nothing proves the scammers are not using those other alternatives for all you know.