The last sentence of the abstract indicates the goal is to be able to run at higher utilization without sacrificing latency. The outcome of that is you need less hardware for a given load which for Google undoubtedly means massive cost savings and higher profitability.

   > Prequal has dramatically decreased tail latency, error rates, and resource 
   > use, enabling YouTube and other production systems at Google to run at much 
   > higher utilization.