You don't need source maps. You don't have to map printed stack traces to the source. Debugging just works. You don't need to configure directories because src/ is different than dist/ for DB migrations. You don't have to build a `tsc --watch & node --watch` pipeline to get hot reloading. You don't need cross-env. No more issues with cjs/esm interop. Maybe you don't even need a multi-stage Dockerfile.
That's for bun. Deno might have a similar story. We did not opt-in to the Bun-specific APIs, so we can migrate back if Bun fails. Maybe we could even migrate to something like ts-node. Shouldn't be that hard in that case.
IMHO the API of Bun, as well as the package manager, sometimes tries to be _too_ convenient or is too permissive.