He claims that "I’m sure what the presenter of the slide was getting at was Clayton Christensen’s definition of disruption from his classic book The Innovator’s Dilemma. ".
He then goes on to say (talking about Square and Uber) that "neither of these companies were disruptive in The Innovator’s Dilemma sense". However, I'd be surprised if the presenter wasn't thinking precisely of people like Uber and the type of "disruption" they've brought to the taxi industry.
So, if they are thinking of Uber, and if Uber's disruption isn't the sort being talked about in the Innovators dilemma, then I suspect they weren't thinking of Christensen’s definition at all.
I'm not sure why disruption has to be less functional - it just needs to be tackling the root problem (and often redefining what that root problem is) in a different way to the incumbent.