I've tried some, but they don't work at all on me.
Success rates with hypnosis vary greatly. I think a lot of what determines whether or not these files will work depends entirely on the individual and how much stock they put into them. Dare I say, you have to be willing to let it work in order for it to work, these files are more than just popping one on and expecting instant results, you have to want it to work on some subconscious level. I also think that some people are more susceptible to the power of suggestion than others, the people who are highly susceptible to the power of suggestion are likely to be perfect candidates for hypnosis.
If these files work for you, you are likely heading into them with the perception that they will work and fulfill the described/desired task and not everyone is able to do that. I personally can't will myself into thinking something will work unless it's results are proven. Oh well, to each their own, if listening to these files makes regression time and diaper usage easier for you, then more power to you.
I find that the only audio files I need to regress are instrumental lullaby tracks, perhaps you can try listening to some the next time you regress, you won't regret it