Is this bundle not going to be available for download later? How is it "Limited?"

Limited Edition is just a name like Gold Edtition.

Might and Magic 6 Limited Edition was a promotional retail package for MM6 that included the first five games, so it's basically what we have here. I agree that it's absurd to call it that here, because it's not a limited edition anymore.

That is a huge relief to me, I just spent my little bit of fun money on the Interplay promotion for the first anniversary, and this (along with HoMM3) were next in my sights, but I was afraid of it going away before my next paycheck. Thanks for the response to original poster's inquiry!