What's even worse in real-world applications is that OpenBLAS misbehaves when an application uses threads. This is also described in the OpenBLAS FAQ:
If your application is already multi-threaded, it will conflict with OpenBLAS multi-threading. Thus, you must set OpenBLAS to use single thread as following.
The reason it's serial BLAS that mainly matters is that HPC codes are usually parallelized above the BLAS; why do you want the nesting? Swapping in threaded OpenBLAS or BLIS is something you might do with basically serial stuff like vanilla R, e.g. https://loveshack.fedorapeople.org/blas-subversion.html#_add... OpenBLAS threading has been somewhat buggy, but the main problem with its OpenMP support currently seems to be that using OMP_PLACES kills it.