Powdered steels tend to take very keen edges and have great edge retention. Some can be very tough to sharpen, while other can be much easier. Most powdered steels have a tendency to "settle"... so, for example, lets say you sharpen a powdered steel knife to 100%. It may settle to 95% (even without you doing anything to it), but it stays there for a very long time.
So, the main point of powdered steels is great edge retention with very fine edges.