I'm one of the engineers on the project, it was great working with the Cloudflare team. Here to answer any questions if you have them.
from the post:
Combining Cloudflare Workers, Hyperdrive, and PlanetScale relational databases allows you to build modern globally distributed applications without worrying about database connection limits or latency. Your Workers run globally at the edge, Hyperdrive provides intelligent connection pooling and caching, and PlanetScale delivers ultra fast and reliable databases for both Postgres and MySQL/Vitess.