OK so I set up a test account an things are mostly fine, although there are still rough edges. For example, onece the static site is deployed and you click Login in the default theme, you get:
> error on line 12 at column 10: Opening and ending tag mismatch: meta line 0 and head
This is after two first minutes, so I guess there are still things to work on. In any case, for more advanced users your product is a great no-no, since the main advantage of WP is that it's FOSS - who would want to become your hostage? I see a lot of potential for an open source solution, the idea is really good.
Moreover the support is just perfect. I needed a Multisite feature and they've added it in no time.
https://mothemes.baby