It doesn't really matter if it's 'just a wrapper', because said wrapper provides an ABI. Even if the underlying Native API changes, the interface the wrapper presents to other compiled binaries won't. The latter will contain caller/callee register setup, type layouts, function arguments and more for that wrapper.

Cygwin is also 'just a wrapper' for the Native API and Win32, and look how drastically it changes the ABI of applications.