Keeping it for customer pickup also creates a security and liability risk for UPS. And there have probably been a lot of claims made because phones go missing from UPS holding care.What? They are not a self storage facility. Their job is to deliver things to you. That is what is certainly more efficient to them.
They are probably tired of dealing with the mass number of people that order it and then immediately hold it at a center to simply to try to pick it up a little faster. If people don’t want it delivered - pick it up from Apple.