I would argue that the lower number is meaningful if the posting in question entertains hiring zero or low experience candidates (e.g. fresh undergrads) for the role. In that situation I would think that most applicants matching that description would be happy to get a salary on the lower end (within reasonable limits of course) since at that stage in one's career the biggest challenge is getting one's foot in the door.

In my experience there aren't many postings like that though, most are looking for at least moderate levels of experience in which case I would agree that the upper end tends to be the expectation.