1. Why do you have to ship a source map? It compiles to vanilla js
2. Not sure what editor, but in neovim (which uses tsserver on my end for LSP) I can either jump to the type declaration or the actual implementation. This is a tooling problem not inherent to typescript
3. This doesn't make any sense. You'd have the same problem with minified js or css etc.
4. It means they are forced to use types properly and do the tiniest bit of thinking and planning that results in fewer type errors (think undefined variables and properties, etc)

Not a bad summary, but I take issue with all the points

Edit: The sourcemap comment is relevant to package size and not to final bundle size per the HN comment linked below. Also, the cmd+click critique rings truer now that I know it's in the context of an installed package. Another critique is build time which is fair enough.