Aldi in the USA also does the coin lock. I don't know why other stores don't do it. Maybe because Aldi is seen as the cheap store and they don't want to be associated with being cheap.
Aldi is a European chain of course, and I suspect they carried that tradition over to their US stores.
I dislike this system. I don't go to Aldi very often, and I never have change on my person or in the car. So I grab a cardboard box (which Aldi makes available to customers) and fill that up as I walk around the store.
