A different question: What is the actual tactical use of combining gun and missile systems, like with the "Pantsir" or "Tunguska" systems?

I understand that a guided missile system is distinctly more expensive than a radar-guided gun system but the only solution for medium range targets. Now I would assume that even if the guns are superior at extremely short ranges and low heights, wouldn't it be a lot easier to have some additional short-range missiles instead of having to construct everything around a gun platform?