Plus, of course, 'public domain' is a very fuzzy concept and in some countries either doesn't exist or else exists in a very different form to the US. It's a legal minefield both the the producer and the consumer; way, way better to ignore it completely and use an OSI license.

(Apropos of nothing, I generally prefer the BSD-2 clause license to the MIT one because I think it's clearer and easier to understand, but they're fundamentally equivalent.)