My point of commuting by bike is so I don't have to ride the subway.
For my commute both take about the same time, an hour or so, and I prefer the bike.
I agree with not taking a bike on the train during rush hour, I hate when others do it, the trains are usually packed enough that adding a bicycle is a pain in the a.
If you're going very far, then the video is indeed helpful but for shorter rides I wouldn't bother.