Interesting, but sounds premature, since "We will support Edge Caching soon, so your REST requests will be cached at all edge locations globally."

Cloudflare Workers are a really great addition to static sites that need just a little wee bit of dynamic content from the backend. It should really be promoted more by create-react-app as a logical extension into back end like dynamically overwriting canonical urls and other meta tags in the static index.html

How does the latency compare in this case?

Redis REST has overhead less than a millisecond compared to Redis TCP. But when EDGE caching is enabled, reads become much faster as expected. Rough numbers we have seen: REST: ~0.70ms REST (EDGE cached): ~0.12ms

Note that, EDGE caching is work in progress. It will be publicly available in a few weeks.