If you're selling, or even giving away, digital products on your WooCommerce store (e.g. Audio/Video files, Zip files, eBooks, PDF's etc…), it's a great idea to offload those resources onto a third party, like Amazon S3 (Amazon Simple Storage Service), which is part of AWS (Amazon Web Services).
Offloading your products to a service like S3 means that your hosting disk space and bandwidth wont be impacted when customers purchase and download your products. If your products are attracting a large number of downloads, or if your products are quite large in size, this can be a huge saving in terms of hosting costs. Using a service like Amazon S3 isn't free, but it will be cheaper than paying for extra disk space and/or bandwidth from your hosting provider.