However, I think (and hope) the point of this service is that by being public, it'll drive prices down for drivers.
I drive 10 miles round-trip once per month to save what I guesstimate is £5 on a tank of fuel, then spend £100-300 in the Costco store while I'm there. I'm not the target audience, but I hope that for those who drive regularly, or for a living, this can help route them to where they can get the best prices as they're passing by.