I run
https://brick.do, which is almost the same thing but with optionally nested pages and CSS.
I might be wrong, but I feel that if you're aiming to make money with this, you have three markets:
1. People who just want to put their own stuff on the internet, potentially/hopefully anonymously, but are not making any money from it. In this case it might be better to have free pages with ads (and write a small script that would try to catch phishing/spam — in my experience, the words "PDF" and "Microsoft Office" have been catching 95% so far).
2. People who actually use it for their business needs (one-page portfolios, business proposals, inventory lists, whatever) — then you need custom domains and possibly accounts but I dunno.
3. People who are doing dangerous things. This applies to drug dealers as much as it does to political dissidents. Then you probably need cryptocurrency payments.
Regardless of what you do, I suggest you create some kind of a public discussion forum (FB group, Discord server) for this project. You can do it right now, and you'll likely learn a lot about what your users want and how they are actually using your product.
At any rate, best of luck. I think it's a good idea and I'd like to have more projects in this space (as someone who wants to start new projects all the time and hates small obstacles).