Baines was better than Barry.
Our CDM depth has collapsed, despite looking strong in pre-season. Gibson is done IMHO. Besic was ill, Barry has been in woeful form since his injury (possibly not properly recovered) and now McCarthy is carrying an injury. Additionally Garbutt needs game time if we are going to convince him to re-sign. Circumstances justified the selection against Newcastle, and I would not be against Baines playing in midfield again because he did pretty well. We ask our CDMs to drop in to the fullback spots to cover when our fullbacks push forward, so it's fairly sensible to assume Baines could handle the defensive side of the transition easily enough. As another poster has already mentioned, Baines brings pace and energy to our midfield and allows us to press the opposition higher up the pitch - this is a good thing. He also has vision, and a passing range and accuracy to make use of his vision.
There's no point whatsoever in selecting Barry or McCarthy if they are carrying injuries. Gibson is never available. That leaves Besic, and someone needs to play alongside him. Your choices are Osman, Barkley, Oviedo or Baines; personally I think we need Barkley playing in the no.10 position, I don't rate Osman as a CDM and I'd like to see Oviedo playing on the LW. At this point Garbutt is a better LB than Barry is a CDM, so the decision is simple IMHO.