What About Autocomplete?
Every decent editor has good autocomplete plugins available.
What About Identifier Name Typos?
Any decent linter can catch those errors.

I can't believe you're comparing the default autocomplete implementations of editors and error reporting by linter to what Typescript can provide. It just seems disingenuous.

Something can be said about how depending on the situation there are tools that are Good Enough™, but, if you're spending hours every day writing code, an autocomplete plugin that suggests random words from the same text file is not going to cut it. Same with errors from linters that can analyze files lexically, but have no understanding of what the code does.