Why do you need to own the Bluray version if you only intend to get an SD version of the edit?
I will say that Bluray, even output at 480i, is far superior to DVD. Color is WAY better, and the clarity does not suffer from MPEG artifacting, thus giving you a crisp and clean image. Definitely still worth it to buy, though not as much as it would be for larger screens/resolutions.
These benefits are lost when BluRay sourced edits are released as a standard DVD.