Earlier quoted context omitted.
A more descriptive word would been self-hostable function as a service, that's why faas is in the name! The point of serverless is you don't have to think about hosting, and ideally it's cheaper. The problem is if the hosting provider goes away you're screwed. In the case of Faasta, it's a single static binary with minimal configuration so if that happens, you can host it your self or move to another provider.
How can you "not have to think about hosting" while self-hosting?
I get the feeling it's basically an old-fashioned application server like Wildfly or Tomcat. So the developer doesn't worry about system-d config or whatever, but just adds their application files to a folder. Of course someone needs to maintain the application server, however it's deployed, but it detangles things a bit. I personally think this makes no sense unless someone else hosts the application server. Maybe in an enterprise context of some sort. Otherwise this feels like a tried-and-failed idea.