I find launchpad a very confusing experience. I'm sure I would get used to it if I used it more but every time I visit it, I am at almost a total loss on where to click and what everything means. Just taking one example, on github, there are very few labels. The content mostly speaks for itself. Whereas on launchpad the labels dominate. I like Bibucket much more than launchpad as well.

But the reason github is more popular probably has more to do with git being more popular.

because.