So even if I could understand filtering out the lazy folks from those who are willing to jump through this particular video submission hoop, why the fuck do they waste people's time with such a ridiculously nebulous prompt? I honestly don't know how I would answer such a vague question for more than 30 seconds.
It works on the same basis as those email scams. They only want the people dumb enough to fall for the scam so the email scammers litter the emails with spelling and grammatical errors to filter the people out that can't be easily manipulated. This employer is filtering out people that aren't desperate and people with any sense of employment ethics or self worth.