Shopify is a hosted storefront that is focused primarily on the eCommerce functionality, but also provides blog, custom pages and photo gallery features.
Con Not a website builder
Often on your web hosting site there is a quick install via cpanel such as prestashop. In other other words, as part of your own website on your own hosting you can have e-commerce functionality. Shopify is a different matter... basically your shop is on shopify co hosting, so technically its not a website builder; rather it's like a stall you set out on someone else's turf.