That's actually not quite correct. The wheel still physically moves as it does on the Mark II, but now also includes the touch controls for video. And Thank God for that, I hate touch sensitive scrolling. It always makes it hard to select things and would be tough to impossible to use with gloves.
Look at 1:18, doesn't look like the wheel is moving to me. I know it has that lock switch below it, but it doesn't appear to be engaged.
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Then at 1:31 in this video it refers to the wheel as "touch pad"
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