When committing aux tracks you often get a lot of silent clips. Committed clips is created even if no audio is sent to the aux track.
In the what's new in Pro Tools 12.3 document it says:
"Committed Auxiliary Input tracks reference the clip boundaries from audio tracks routed to the input of the Auxiliary Input track and preserve them whenever possible."
This is not very useful in large session where you can end up with several gigabytes of just silent audio files. The –144 dBFS audio signal threshold that is used on audio tracks should be used instead of referenceing the clip boundaries from audio tracks routed to the input of the Auxiliary.