I think it is more a skill issue than anything else.
Yes, marshaling has a visible impact, hence why one should think how to actually make it happen, not much different from using FFI in any other programming language, there is always an impact over staying in the same programming language.
Compilation being harder, only if the developer is not acquainted with C, which seems to be something harder to learn nowadays.
Signal handling is a mess even in pure C, especially since all UNIX implementations added threading support.
Yes, marshaling has a visible impact, hence why one should think how to actually make it happen, not much different from using FFI in any other programming language, there is always an impact over staying in the same programming language.
Compilation being harder, only if the developer is not acquainted with C, which seems to be something harder to learn nowadays.
Signal handling is a mess even in pure C, especially since all UNIX implementations added threading support.