I always know Lorraine has my back to give good newbie advice. Yes, 10 lbs is too light to do swings. The video doesn't use recognized, traditional KB moves, although it does have some 'swings' in there. She doesn't do swings correctly and many of the things she does will likely get someone injured.
There's a thread on here that cites the recent ACE study about kettlebells. It states you can burn up to 20 calories a minute, which is true for that particular type of workout, which is a very advanced workout.
That being said, using a heavy bell for swings burn an amazing amount of calories and has the benefit of providing cardio and weight training.
If you're serious about using kettlebells, look through the threads and also read some articles on Dragon Door. They're amazing tools to work with and well worth learning.
Strength does not come from pysical capacity. It comes from an indomitable will.