Apparently, not a hack job but aftermarket equip.
From the video description:
Bolt on tank tracks on a modified Jeep Willys powered by a Buick V6 engine.
The Tracks were manufactured by a company called "A. F. Wagner Industries Inc." of concord California. They were made sometime during the mid 60s and there was only 6 sets made and were apparently expensive and thus may be the reason there were so few made. They are called "Wagner-Trac" and were made specifically as a set of tank tracks for a jeep with a wheelbase of 81 inches. The wheelbase is not adjustable so the wheelbase is critical and just like a tank you would have to install turning brakes to drive the Jeep because the steering is null and void as soon as you bolt them on. They are all steel construction so were probably designed for offroad only.