“SSL” is short for Secure Sockets Layer. Adding an SSL creates a safe connection for your visitors plus it makes your site more secure from attacks. Before it was only required for e-commerce websites, but now Google Chrome will give visitors a notice that your site is not secure if you don't have an SSL on your website.
Before dismissing your site as too small to be a target, bear in mind that most interceptions are done electronically without a human deciding who is attacked. A web creepy crawly doesn’t care how big you are or what you do for a living. They have one goal, and that is to find vulnerabilities. Once discovered, its dirty work begins.