All prominent DAWs (Sonar, Protools, Cubase, Logic) and even "smaller" ones can export to MIDI. This is not possible in SO.
Many composer of complex music use MIDI as basis before going to Waves.
MIDI is also preferred as method in many collaborations - it is much easier to edit than waves; and alternative sounds can be heard very easily without re-recording.
I know composers who are not interested in SO because of the lack of such a basis function.