Netlify is fantastic. It simplifies deployment and delivery of the websites dramatically. What Heroku did for app development, they did for websites. And even though they are nominally static websites, you can wire them with React or Vue and still have apps.
Agreed. I've switched out my complicated GitHub+S3+CloudFront+Cloudflare for static hosting to Netlify. Netlify also handles some of the stuff you don't even think about - e.g. partial deploy failure. With my past scripts I might push `index.html`, lose network, error out, etc, and not push the updated `assets/blah.css`.
They're a static site web host. You deploy using git, and they handle pulling your site from git and deploying it to a CDN. If you're using a static site engine like Hugo or Jekyll, they'll build the site for you as well.
I think what people are excited about is deploying a JavaScript-based frontend (probably written in React or Vue.js) using Netlify, so the client-side code is quickly distributed and accessible.
Building Javascript-based frontends are already compiling to static assets, which Netlify could already host. JAMstack is about having the javascript front-end call APIs on the backend. This is about creating an environment for all the back-end functions to be in one place, possibly with the front-end deployment. Not sure how it is going to be implemented though.
They make my life easy.