Delta Air Lines' recently announced decision to base frequent flyer rewards on dollars spent rather than miles traveled is a better, more customercentric way to distribute product benefits, says Wharton marketing professor Peter Fader. When it comes to customer value, Fader notes, "one of the rubrics we celebrate is the notion of RMF — recency, frequency [and] monetary value. [It makes sense to] reward customers on that basis." With just 4% of Delta's customers accounting for 25% of revenues, the choice seems clear — if overdue — Fader explains.