Advertising, pure and simple. Terms are just being used interchangeably, just like different DVD companies use "Anamorphic", "Widescreen", "16x9" and "Enhanced for widescreen" to describe the same thing (and occasionally inaccurately.)
I love how many current DVDs refer to "menus" as a "feature" on the back of the case. It's not a feature...it's the standard. It's like saying "Buy our car, it's got TIRES!" LOL