Yeah, that's my immediate debate in reading this blog post: `deno pack` might be a great replacement to my existing `npm publish` workflow for my open source packages and continue shifting my work to Deno-first/Deno-mostly, but on the flipside, with Node's growing TS support I'm also considering switching to Typescript-only npm packages as a (tiny) message to the ecosystem.
Though I'm also happy that JSR exists as that (mostly) cleaner ecosystem.
Node refuses to support TypeScript within node_modules, see https://github.com/nodejs/node/issues/58429 this means you can't do "Typescript-only npm packages".
They made that intentionally at the beginning:
> Currently there is consensus that Node.js should NOT run TypeScript files inside `node_modules. It is not supported to avoid package maintainers to release TS only package.