It is when pretty much every new car has a large screen on the dashboard, usually well out of the driver's central view, using which various control functions must be carried out and satellite navigation followed. This is apparently legal.
A two-inch screen half-hidden behind the mirror and showing a subset of the view through the windscreen can hardly be considered a distraction in that context. Certainly less so than the rear-view mirror itself, at which the driver is *supposed* to look from time to time, taking his/her eyes off the road ahead to do so.