Low bar position does not mean less knee travel, in fact, in the style of squat Steven is referring to the knees track forward quite a bit compared to a traditional wide stance, low bar, hip squat. There are plenty of lifters who squat high bar with very minimal forward knee travel and sit the hips back very far just like there are plenty of low bar squatters who allow the knees to drift forward and sit more straight down rather than back.
The bar position is simply giving you better leverage on the bar, what you do from there will determine the other things mentioned more. One big advantage of using the low bar, moderate stance, knees tracking over feet, style squat that Rip preaches is it allows the knees to track forward with much less pressure on them due to the bar position. I have had several athletes used to high bar squatting with lots of knee travel simply switch the bar position and still maintain nearly the exact same squat with that one exception, the difference in the stress on the knees is huge, the low bar position greatly aids this issue.
For athletes who are jumping, running, etc, and also squatting, I like to use that style of squat MOST of the time, I have found that it is easy to teach and greatly reduces the stress on the knees, strengthens the hell out of the hamstrings, and allows more weight to be used than other styles. If someone is comfortable with another style then by all means I have no issues with them doing that, the most important thing is that you get a style of squat that you are comfortable with and believe in, if youre always guessing wether or not you should be doing something else you will not get optimal results from anything youre doing anyhow.