When switching either voluntarily or involuntarily to ATTI, doesn't the drone still hold altitude? I have found pretty solid altitude hold even in strong winds.
I think anyone that flys a drone should be able to fly it without the nanny net if something fails. It's not hard and stops that 'run away drone' thing which is pretty embarrassing.
On my second flight drone flight ever on my brand new (at the time) P3P, the GPS glitched right after take off and it started drifting BADLY. I watched to see when it was going to come back and it didn't as it drifted towards trees. I easily pulled it up but as it was facing me you need to know your orientations to stop it. Those 'drone + garage door' moments don't look good in hindsight and are expensive.
I personally wouldn't want to risk a two grand drone for a shot myself. They are expensive and not easy toys/tools etc to replace/repair (they are either going to get totalled or need to go to DJI and won't likely be around for a month or so -
P4P gimbal alone is about a grand here in Aus and that's guaranteed to be destroyed in a fall).
Cool shot OP. You are pretty game though!