elmoglick, you've got a pretty good grasp on the concepts now.
And yeah, it's a bit of a tradeoff.
Page already has a meaning, so it makes sense to reuse it in the context of eBooks. But the catch is that a single page can be across multiple screens, or multiple pages on a single screen. This is still no worse, and in some ways better, than paper books though. When citing a book, you have to specify the edition, or the page number is meaningless, since each edition has different numbering for the most part.
Locations are a whole new thing, and so there is some 'training' involved. I remember a lot of early complaints that Amazon should have just used page numbers on the first Kindle. They seem to have gotten over this hurdle though, as I've not seen any complaints recently.