They are great in performance but the problem is that the libraries designed and developed in native C language and could be used in unmanaged C/C++ programs. Today many of programmers used to program in managed language such as C#, Managed C++, ... in dot net platform. Using unmanged IPP and MKL libraries in Managed languages are so hard. I think designing and developing a managed object oriented Interface for these libraries would be great improvement that will bring easy to use performance gain for all new programmers.
With so much server side development happening in c#, you should have wrappers for c# an MC++ for all Intel SDKs.. Otherwise talking to these SDKs it too much work and usually we go with other solutions.
one remark: Currently we have no such wrappers for any of these libraries but for those who arе interested in this question, we would like to recommend look at the article "Using Intel® Math Kernel Library and Intel® Integrated Performance Primitives in the Microsoft* .NET* Framework". Please follow this link : https://software.intel.com/sites/default/files/m/d/4/1/d/8/Using_Intel_MKL_IPP_NET_Framework.pdf