This is a good article that speaks to several of the benefits of the Spiff solution. Setting quotas/targets are much more effective if you have data to back them up. We offer so much useful data that allows leadership to set "real" quotas.
""Having an objective, evidence-based methodology for setting sales targets goes a long way to motivating the sales organization to grow revenue. Salespeople put their efforts toward selling rather than expending unnecessary energy questioning and negotiating sales quotas."