As I pointed out in another thread, "irrational behavior" can have the effect of precommitting. For instance, people "irrationally" drive at a cost of more than $X to save $X on an item. Precommitting to buying the cheapest product even if it costs you money for transportation means that stores are forced to compete with far distant stores, thus lowering their prices more than they would otherwise. But you (and consumers in general) have to be able to precommit to do that. You can't just change your mind and buy at the local store when the local store refuses to compete, raises its price, and is still the better deal because it saves you on driving costs.

So the fact that you will pay more than $X in driving costs to save $X can be seen as a form of precommitting, in the scenario where you precommitted to following the worse option.