I might be missing something. How does this compare with netlify which I've been using sometime as my 'heroku' for static sites? With that I'm also getting the ability to post-process things, use lambda functions, even get get forms for free (up to a point) which is needed for almost every site. It also provides slick DNS. Has worked wonders with gulp/jekyll/etc builds. This does seem to do all of that with the exception of forms.
If this is just another choice that's good. Perhaps it's faster? I've deployed using zeit and it is a really smooth process but not much different than netlify's build that works with a git push. Either way, congrats on the funding!
Disclaimer: I don't work for netlify, though I did interview with them awhile back.