Thanks for the answer. Now I get a bit better idea when it comes to saving time/resouces.

Another thing seems to be clear is that TS devs need to be more skilled. So interchanging them might be of a slight issue.

What do you think?

Maybe differently skilled? If all you have are front-end engineers, then TS will require a different skill set since front end guys don't usually deal with typed languages. If they have experience in other languages, it might be fine. But if they've been in the front end a long time, it might be hard for them to adjust.

Right, this is an actual reason why someone may have friction working with TS and it is better not to choose that developer.

But still the question stands. Like imagine we compare web game dev with JS vs C++. Obviosuly you need to plan much for testing and QA engineers need to be more skilled when we talk about C++.

And also I as a PM will plan from the start that using JS and corresponding framerworks might limit me in what I do.

Same thing here with TS vs JS. The question stands :)