I suspect the guru meant the "change filter" button and misunderstood it.
The system level auth/authorization_trace is not a detailed user based trace. It is a collector mechanism for the transaction contexts to write entries into table USOBT_AUTHVALTRC to record which objects were checked with check values in a transaction. SAP uses it to propose values for SU22. SAP developers process it in transaction CHECKMAN. If maintained / transfered, then they land in SU24 when you process SU25 steps.
SAP released parts of this for customers as well to record "original data" for the customer system, but you will be given a warning about paralyzing the system if you turn it on because at every AUTHORITY-CHECK statement it compares the check data in the kernel to the application table. So it is ok for DEV and QAS systems to collect data for SU24, but for larger PROD systems you should be very careful (I do not recommend doing it in PROD).
Cheers,
Julius