It’s more for library devs when writing their libraries. Using TS means you’re writing in one language and then distributing the compiled version for users.
As users can use things in a lot of different ways you have to do a lot of type “gymnastics” to make your library API as useful as possible.
That means spending a lot of time setting up types when a jsdoc and .d.ts file will do the same thing for library consumers.
It’s really a non issue. If some library devs think they can ship code which is easier for them to maintain correctly, and end users have the same developer experience, then it’s totally cool.
Of course people with no nuance are using this as an argument for why no one should write in typescript (because they don’t like it for some reason). This thread has a bunch of people doing this. That creates drama, but there really shouldn’t be any. TS is bae for me, but I totally get why library devs might want to not use it.