They do have relational DB connectors [1], which have been working great for us. But maintaining a centralised DB is still a bit of a pain and latency can be high, depending on where users are accessing them from. Having a managed, distributed SQL service will be easier to manage and will likely have much lower latency. Their SQLite DB, D1 [2] looks interesting. But would be awesome to have Postgres' more complete feature set as a managed, low-latency service
[1] https://blog.cloudflare.com/relational-database-connectors/ [2] https://blog.cloudflare.com/whats-new-with-d1/