The main difference between these two types is the amount of control you have and the technical knowledge you need to run your website.  With a self-hosted platform like WooCommerce, you control the site, and the technical limitations come from your web host. You have to take care of the website's technical aspects yourself. On the other hand, a hosted platform, like BigCommerce, gives you everything you need in one package, and you can leave the technical stuff for the platform's support personnel. The subscription level determines what you can do with the platform.