Can someone knowledgeable please explain where these workers are useful?

Serverless components within an main infa. make sense - it's an easier way to deploy.

But these 'edge' functions ... what is the advantage of saving a few ms on a transaction?

I understand that we may want standard content pushed out to the edge, but in what situation is it really worth all the added complexity of risk of pushing out functions to the edge, to save a few ms?

It's often not actually more complex, it's simpler. With Cloudflare Workers, for example, you don't think about regions, availability zones, provisioning resources, or cold starts. You just write code, and it can scale from one request per second to thousands without any thought or work on your part, partially because of how its designed and partially because it's scaled across so many locations and machines.

> You just write code

Except you need to do it in a totally new paradigm (serverless) where you can't require any `npm` packages and you can't query your database unless it's over the `fetch()` API.

You just have to introduce a build tool like ncc (https://github.com/vercel/ncc) which will bundle your app into a single JS file.