The ability for us at our venue (a concert hall) to be able to see who is attending events there by tracking attendance with QR codes or just looking up people in an app was great! I didn't like that we couldn't get more info about each person's attendace than what was shown within the app/website - but maybe this could have been made clearer? We were also unable to track how many tickets had actually sold after someone bought one from another site outside of ours.
This would help give accurate numbers if it allowed you to check which ticketing sites your clients are coming across most often when selling tickets. It helped us keep records of where new members came from and kept everyone informed of any changes regarding membership fees etc.