Matlab works very well for many disciplines and the shear amount of documentation make it very easy to use for people who aren't really programmers. My main peeve with matlab is that to write a function it is required to make a separate file however most problems that are solved with matlab don't really need functions in the first place.
SciPy/NumPy and matplotlib can be nice to use but if I need to get an engineering problem done quickly I can find functions that I need much quicker in matlab and the matrix as the central object is very helpful.