10$/month is 120$/year. Plus you have to do more work on top of that to actually build the site and integrate with a CMS.

Notion users will be in for a nasty surprise when they realize that DO is closer to a Raspberry Pi than a OEM PC.

All you get is a barebones OS without a GUI. You have to set up everything yourself: server (e.g. Apache), language (e.g. PHP), database and SSL. This is a non-starter for people that have never seen a command line interface before.