(you ask me, though, it's a tiny pee-pee thing)
The bike could not be made to countersteer (would not lean in a turn), so it could only be safely turned at 10 mph or so, max. (It steered like a trike, but without the relative stability).
It was, (like this bike appears to be) great for going straight or on a road with very gentle turns, but forget doing anything with real curves.
Fun to play with at a run, but nothing I'd want to drive there.
Note, though that that tire was not rounded off like a motorcycle tire, but had pronounced corners where the sidewall met the tread--it was not designed to be used on a motorcycle. The bike had no kickstand, either--it stood on its own.
Just from the appearance of this bike, with the long wheelbase and fork angle, it would go straight well, and tend to be stable as long as it did not frame out on anything, but the bit about it not turning well is probably a masterful understatement. I would think that as long as the rear tire was intended to be used on a motorcycle, it would not have as much affect on handling as the chassis configuration.