It's always easier to use a single button than multiples - the fact that they're colored makes it easier to customize them for each function and easier to find. e.g. - on my DirecTV DVR when you're in the program guide the red button takes you 12 hours back and the green button takes you 12 hours forward. I don't think there is any other way to do that and since there are no dedicated color buttons on my 720 I had to map two of them to unused hard keys and put the other 2 in the LCD.

By contrast, the red button in the program listing deletes a recorded program. This helps reduce the number of dedicated buttons on all remotes. Satellite and cable boxes are starting to use these more and more.