Why is there no `libcurl.4.dylib` under /usr/lib ?

When I want to add libcurl as a dependency I add libcurl.4.tbd under Link Binary with Libraries and it works. As I understand it these tbd files are stub libraries to enable the linking process for dynamic libraries while keeping the Xcode SDK download small (by replacing the actual dylib with a kind of placeholder).
When I open the libcurl.4.tbd in Xcode, it lists under install-name /usr/lib/libcurl.4.dylib and I expected to find this file. But I can't find the actual libcurl.4.dylib at this dir nor anywhere else on my system. otool -L gives me same filepath.
How is the linking handled in this case and where is the actual dylib located?
I've learned that libcurl.4.dylib actually resides within a shared cache file unter /System/Library/dyld.
I'm running macOS 11.1

What's the benefit instead of just placing the dylib under the specified path like /usr/lib/?
Why is there no `libcurl.4.dylib` under /usr/lib ?
 
 
Q