TypeScript is becoming more and more ubiquitous and I think that is a good thing. 4 years ago, I argued that valid JS is not valid TS, but TS has matured a lot since then.
I would also go as far, to teach new programmers TypeScript from the start, rather than JavaScript.
JavaScript involves a lot of guesswork or try and error if you know nothing.
How do you explain to someone that some DOM event _will_ have a special property they should consume? REPL-based programming is still a thing for trying out that kind of things and it helps greatly to learn about the return values (or types) of functions. But once you know what an event listener is, what you can attach it to, you really want to rely on signatures right off your editor. Code is documentation too, and TypeScript enables code to be self-documenting in a way. If implemented correctly, I don't have to try out functions but simply know what they do by looking at their signature, which means a great productivity boost to me.
We still have a large gap between the developers that sprinkle in JavaScript as additive for some special effects on regular websites or full-blown web apps that have devops baked into them. Think PHP in ~2010. There are still people using FTP to deploy their websites, so an extra build step comes with a huge up-front cost you probably don't want to pay.
In these places, usage of TypeScript is kind of a gray zone, as you cannot rely on completely automatic deployment.
Which is why I am looking forward for the type annotation proposal: https://github.com/tc39/proposal-type-annotations