I thought the way React did suspense was pretty elegant?

The component render function is pure, meaning you can re-render component without unwanted side-effects. So on encountering an unresolved promise, halt and throw the promise, then have the runtime catch the promise and re-execute the render when it resolves. I thought this was really an elegant way to introduce an asynchronous dependencies.

It only achieves purity by re-defining the pre-existing concept of "pure". Component state is not passed as an argument, and can affect the output of a render function. It's only by playing semantic games that react claims to be pure, which I find to be of dubious value in this domain anyway.