Exactly. This is why I currently don't have much interest in a Keytron, because with a decent enough GM soft synth/sampler, I can prototype songs at the coffee shop on my netbook, then later, transfer the MIDI to my DAW, where I have all sorts of high-quality sampler and synth options available.

But I would imagine that if you don't have a lot of soft sampler and synth options, and/or the horsepower of your machine won't support a bunch of these, then a Keytron would be a good choice.