By the very simple fact that almost every edition of D&D is for sale as PDF, they have recognized this for quite some time.
I would buy that IF they only put up the older edition materials AFTER 4th edition became available.
BUT, the fact they didn't take those down when 4th edition came out, could agree that they know 4th is not all people will buy even though they only offer it in their current product line.
So having the tiles work with those older PDFs and even OGL material and saying so, just allows them to appeal more to a greater audience rather than just saying "for 4th edition" which some may bypass the product entirely as seeming to be made for, or only work for use with 4th edition.
So it is still a better way to word it than claiming for 4th edition, but the PDFs show nothing until they take them down.
IF they allow OGL/GSL scaled down versions of the map tiles in products to promote the sale of the tiles with the old PDFs as well as new products from 3PP, then it would go a lot farther to support older editions.
Nonetheless it is a small amount of support for older editions in the right direction.
Warning: don't drink coffee and eat BBQ because, it leaves you with more energy than you know what to do with and ends up with long posts.
