As I said here (https://news.ycombinator.com/item?id=7032169 https://news.ycombinator.com/item?id=7032169) it's usually because of front-end performance. Users

As I said here (https://news.ycombinator.com/item?id=7032169 https://news.ycombinator.com/item?id=7032169) it's usually because of front-end performance. Users are very concerned with performance, and loading a 150kb library doesn't help. The extra kilobytes translate into seconds at an alarming rate if you're not on Google Fiber, and I've found that in rural NH Bootstrap usually takes 3 seconds to load vs. Min takes 300ms to load. Min (http://minfwk.com http://minfwk.com) is a 995 byte CSS framework I made to deal with the slow loading times of other CSS frameworks.