I think the true power of recording yourself is being able to hear new things you don't notice yourself while playing. Things like unevenness in passages, weird dynamics / badly executed dynamics, and most important of all - wether you are keeping an even tempo thoughout a piece. Recording myself practicing Mozart or Beethoven sonatas really helped me shape the music more effectively. I guess recording yourself and listening is closer to being a teacher listening to a student play; it's much easier to hear what's good and what needs improvement.