>>739I don't know about Azumanga, but it may have been made at slightly higher than DVD quality and thus this could give us a bit more quality.
Alternatively, and again I'm no expert, but we could also potentially get a better "encoding" (may be using the wrong word here) of the same file with less artifacts, better colors/color balance, etc.
But you are right, this could be the literal same content from previous DVDs.