We've used Netlify at previous projects, we used it because it was easy. No AWS accounts or knowledge needed, just push to master, let the CI build (it was a Gatsby site) and it was live.
I think Netlify is great but to me it's overkill if you just have a static site.
I understand that Netlify is much simpler to get started with and setting up an AWS account is somewhat more complex. If you have several sites, it's worth spending the time to learn.
