Mainly so you can keep up with them, view their opinions/answers and maybe even help them later with further questions they might have. It's also good to learn from them even when it's not one of your questions you can view the ones they answered just to gather that much more information.
Hi Justin and welcome to ask :). The point in following someone is so that you can stay in contact with a user. If you agree with what they have to say, find them funny, interesting, whatever. You can keep up with their questions and answers easily. That's it :)
When I first came on this site, I followed the people that gave calm, informative answers. I have found some folks to be an excellent resource. By following someone, you can stay updated on their input. Welcome to the site !