I don't see much trouble context switching between HTML, CSS, and JS on the frontend. I don't see much trouble switching between some other language on the backend and SQL, JSON, macro, etc.
Context switching is a real thing, and sometimes creates penalties. But sometimes it increases productivity. For me it is very helpful to switch into SQL mode when grabbing data from a store, then switching to Go/Python/JS/Rust/C++/Ruby/etc thinking for the business rules around that data.
Frontend JS and backend JS are not really the same language or environment. They are different in important ways. But they are so very similar that it can be easy to be in "frontend" thinking mode when working on the backend, or vice versa. And I have many many times seen that cause problems.
That's not to say that it is bad to use the same language in both places. I'm just pointing out that there are pluses to context switching as well as negatives.
Context switching is a real thing, and sometimes creates penalties. But sometimes it increases productivity. For me it is very helpful to switch into SQL mode when grabbing data from a store, then switching to Go/Python/JS/Rust/C++/Ruby/etc thinking for the business rules around that data.
Frontend JS and backend JS are not really the same language or environment. They are different in important ways. But they are so very similar that it can be easy to be in "frontend" thinking mode when working on the backend, or vice versa. And I have many many times seen that cause problems.
That's not to say that it is bad to use the same language in both places. I'm just pointing out that there are pluses to context switching as well as negatives.