Netlify's core USP appears to be making the process of deploying and operating a static site easier - auto-deploys from GitHub in build process, HTTPS cert management, simple CDN config etc.
Claimed 'performance' gains come from static hosting closer to visitors but AFAIK their CDN runs on AWS, and relies on nginx which means HTTP/2 prioritisation is broken - they've got a lot of work to catch up with Akamai, Fastly or Cloudflare on this front.
The whole JAMStack approach seems to result in companies re-inventing the wheel in non-performant ways - Contentful CMS delivers sites via Netlify but all the content is requested as JSON which JS components then render to the page.
Taking away the deploy pain is definitely a win for many of use but it's something I could imagine Cloudflare launching, which coupled with their other features - image optimisation, edge workers etc could probably blow Netlify out of the water