This is true, abacus, but Roland (and several others) do the same thing on some styles. But if you take a Yamaha style, and convert it to Roland (or whatever) you have to remove all the Mega information controls (they have no equivalent in Roland) for things like pick noise, chord damping (this one is especially important - it sounds completely different to just stopping the note with a note-off), body knocks, etc..

The end result is a loss of the realism that the original Mega style had. You still have the notes, but the other stuff is gone. If a simple conversion of the notes where all that was necessary, all would be fine. But there is a LOT more to a guitar performance than just the notes... Although they may have STARTED work on those Mega style guitar parts using MIDI guitars, all the rest of the Mega information was added afterwards in editing...