Definitely not true that you can walk the length of the entire strip in ten minutes. The strip is not super great for pedestrians because you have to keep walking up, around, and through various escalators/bridges/casino entryways. The strip would be much more pedestrian friendly if they closed the main street to cars and let you simply walk at ground level in a direct line.
Anyway, it takes over an hour to walk from one end of the strip to the other. You really do need to pick a nearby hotel, not any strip hotel. And no idea what you're talking about re: walking underground. That's not true for most strip hotels.
But yes, on your overall point, I agree that Las Vegas is a good spot for conventions.