> map anything you wish for your sound synthesis in a DAW
1) It's a pain to set up, and unless you'll bother to populate your default project template with every VST you have (and if you have Reaktor or Kontakt, with every virtual instrument inside that VST), you'll have to do it every time.
2) Doesn't get you the full feel of the real thing. Instead of a knob that has min and max positions and is in the exact position you expect him to be, you have a plastic thing that will not give you any real tactile feedback.
3) It omits a lot of sweet limitations of physical gear. With real synths, I personally prefer simple machines that you can, or better, have to patch from memory: (1) every time you set the sound up, you're forced set it up a little bit different to your liking, so the patch evolves over time and (2) you have to get imaginative in a live situation, and sometimes play the synth while you're in process of going from one setup to another.