What does "Day And Date" really mean?

I think “day-and-date” is an unusual term walking amok as a warm up.

This morning I was reading a couple articles about “day-and-date” deals. Here “day-and-date” refers to no delay between availability of video (or other) content in one form and another, a hot topic in regards to Netflix, Redbox, Blockbuster, and Hulu, and certain to get hotter as more people use these or they die off.

I believe the origin is “same day and date” and it comes from the film industry, but what’s wrong with “same day?”