Resolution:
Programs that require certification only for the duration of the program process can choose a process-based ledger.  Once the process terminates the ledger file is no longer available.

Programs that require certification that transcends process termination and program restart can choose a file-based ledger.

Therefore, a file-based ledger preserves certified delivery information beyond transport invalidation, or process termination and restart.  A memory/process-based ledger does not possess these characteristics.