Because of updates and convenience. You could always use bower or the CDN alternatively. But since npm is the way I use most of the stuff I develop, that's what

Because of updates and convenience. You could always use bower or the CDN alternatively. But since npm is the way I use most of the stuff I develop, that's what I recommend. You don't have to use node to use npm, but as a package manager it resolves lots of issues even for front-end components.