Assuming that your sensitive data is a key part of your product offering (and if it isn't you shouldn't be storing it imo) - wouldn't logging all decryption requests just generate a lot of noise during the day-to-day operation of your application? I struggle to see a scenario where what you described actually increases the real-world security of your data, beyond allowing you to do a more in depth retrospective of who took what data (which can be achieved without the overhead of double encryption).

In the event that some DB creds get leaked or brute forced or however, to the application/DB those creds will look just as legit and any irregularities would only be discovered at best while the data is being taken