Advantages of unmanaged code

tl;dr: Why would I ever choose to write/compile unmanaged code?

Memory managed code has lots of advantages:

1. You do not have to worry about explicitly garbage collecting (which is fiddly)


2. It is much harder to memory leak


3. It is trivial to implement - just choose the correct language or right compiler flags
   
   
   
   • e.g. use C#, or use MCP for GCC
   
   
   
   

However unmanaged languages exist with unmanaged flags, so there must be some reasons for choosing it over managed code. What are the reasons?