I can't imagine many instructors going for this, looking at how much stuff ends up on u-tube etc.
With a trusted student or a friend it would be fine. Or perhaps the odd flight, but the whole PPL? I doubt it. Also 99% of the footage would be utterly boring - I can vouch for that from my flights. I often video really spectacular bits like bits of a flight across the Alps; they are good for trip reports. But from inside the cockpit? Not a lot to see there.