Offline jobs are an interesting idea, but they weren't what we were really thinking of. Instead, we use stenographer more like a database of recent traffic. Consider this as a simple use case for intrusion detection:

  set up snort and steno
  foreach snort alert
    request all packets in stream from steno: srcIP,srcPort,dstIP,dstPort match
    OR request all packets on that srcIP,dstIP, to get OTHER connections between those hosts
    store pcap to directory (or central DB, or whatever)

Then, when a human analyst wants to investigate the alert, instead of getting the very limited PCAP that comes out of snort, they get a ton of data they can use to build context, write new detection rules, etc.