Where did you see self hosting is a pro feature? My bad if the website gives that impression. It will be free, the whole codebase is MIT licensed.
For all the extra bells and whistles, it’s mainly for people who are doing community support at scale who need it which would be paid customers - I do sort of need a way to support myself so I can buy groceries. The core of the product that matter is free and working well for indexing content so now the focus is “what else can we do to improve community support as a whole?”
As for self hosting, if you submit a PR for supporting it I’d be happy to get that merged but it’s not really a priority at the moment. The codebase is setup to be pretty easy to make a self hosted version though.