Well, they want the face on the TV to match the person they're trying to smear. All about the visuals, you know. But I'm sure they'll have a good go even if they don't get the matching faces.
Of course that's part of the reason Trump won't appear in person – he doesn't want to look like he's on trial, even though he is.
Well, that and his inability not to commit perjury, his word-salad problems, and the fact no one wants to deal with his temper tantrum at being questioned or embarrassed.
The Republicans are too scared to let their champion be seen in his full glory by the American people.