I think for me, the key difference is kind of an abhorrence of silence. In an Actual Play setting (I do a podcast and streamed games), there's a sense that there can't be silence, that we have to always be "on." That can lead to some good things, though, where there's more pressure to talk things out quickly and go with our guts--we've had some fantastic "yes, and" moments in our podcast because of this, for instance. But sometimes it's nice to be able to be quiet for extended periods.
There's also a lot of pressure to serve an over-arching narrative. It has to be narratively satisfying for the audience, which means some paths may be closed off (like Anna Landin mentions above, where things can have a slower, more organic pace). I don't think that's BAD necessarily, but it's a major difference.