It isn’t just free. It’s effectively anonymous.

Most hosting (eg AWS) requires you to say who you are, provide a lot of ID. I think some don’t at first (eg Azure, Hetzner) but eventually you need to pay via a credit card, include your actual name etc.

With Cloudflare, you literally only need an email address. It continues to be free.

The second best is Hostinger, where you can pay with crypto.

Github pages is great too, but you don’t really get all the power to customize your own website.