If you need to work with many different inputs (mics, other audio devices) in a studio or home studio context, then you might be better with SPDIF and your multi-channel audio interface. Neverthless, if the KPA can function as a clean audio input for guitars and an easy way to record the profiler output - very handy with just a laptop for example - then this will be very useful. If the MIDI inputs could also be used for recording (using the KPA as a thru box for a keyboard for example) then you would have a very flexible setup with just the Stage and a laptop.