Having the engine off means less airflow over the elevators and reduced pitch authority. Being in a taildragger, rolling down 'rough as f---' earth, covered in rocks, massive divots and vegetation, the risk of nosing over seemed rather too large for comfort. Nose over on a 1:1 slope dropping off a mountainside and you'll have a really bad day.
Impressive, ballsy, eye opening, 'a bit of a laugh' etc...YES.
Airmanship, sound judgement, responsible, safe....NO.
Funny how there are always a few who accuse those who question this sort of flying as being miserable old fuddy-duddies. However, when you get into an aeroplane as pax, do you want your pilot to be some balls-out, adrenaline junkie, risk taking, barnstorming cowboy. No, thought not.