We'd like a way to way to retroactively look at the data and answer questions like, "If you had this rule in place, it would have blocked this many chargebacks" or "...it would have impacted this many transactions".  

Merchants would like to use this to evaluate efficacy or relevance of a rule they are writing.

From a competitive standpoint, Stripe Radar has a capability like this that looks at historical data as you write the rule, and multiple merchants have asked whether DFP can do the same.