1. Speed of availability
2. Video quality
Overall, it’s a better experience that makes it a better alternative. Money isn’t a factor I believe. BitTorrent is better than Hulu (or any on-demand site I’ve seen), just like Blu-ray is better than DVD – it’s as simple as that.
It’s not like piracy is hurting the movie business at all. In 2010, theaters around the world reported a combined total revenue of $31.8 billion, up 8% from 2009. Sure, the number of tickets sold is down, but they can (and will) offset that with higher ticket prices.