Cool, cheers.
I presume you find it a lot better than just writing some notes afterwards.
Is there anything in particular you focus on when you're listening back to them?
I might not be the best example regarding that, because my discipline with the work I should do post-approach is not the best (I have never taken any notes even when I was not recording).
I find useful to listen afterwards to detect some patterns in girls reaction and some stuff the girls said that I might have overlooked in the moment. I find it also useful to see how my voice was doing and what I can improve about it, and to get ride of useless quirks or habits.
So basically for me this is about better awareness of girls reactions and intentions, and monitoring my non-verbals.
Regarding verbals/conversation, I debrief in my head right after the approach, so this is not the area where I find it the most helpful.
Also, a nice side benefits of recording interactions is that when the interaction goes well, I find it really cool to have it recorded. I love to listen several times good interactions, even months after, as I guess some people watch their holidays photos, as nice memories.