I'm pretty sure its just a gimmick, because i think DVI can put out the same resolutions as HDMI, the only difference being HDMI can also send out HD audio as well. So, what good does that do anyone, as most monitors don't even have speakers.
Are you talking about monitors as in Computer monitors or like TV's? And lots of monitors do have speakers built into them, they're just naff so no-one uses them...
Yeah, Id imagine the designers were thinking about TVs as well as monitors. Besides, having audio is a bonus in itself.