Why use Reason with ReWire? While Reason is a complete music tool in its own right, you might want to use other elements in your music, such as special software synthesizers and effect plug-ins. Connecting Reason to another application allows you to integrate your Reason devices and songs with other type of music and recordings, etc. By recording Reason tracks onto audio tracks in another audio sequencer, you can also continue processing your Reason tracks with other software plug-ins.