I forget what the original post contained so I can only base my statement on the title.
The only advantage BD was to Sony (I'll assume we're talking about the PS3 since this is a gaming site) is the storage. All systems (with the exception of Wii) have a lot of focus on HD content with great audio and I expect some games will suffer because of the lack of storage space.
So yes, I believe that the BD is a success and a benefit to Sony.
Also, anyone who watches HD on a regular basis cannot go back to SD... there is a big enough difference to be appreciated.
Edit for restatement of question:
Maybe I missed something, but how was Sony benefiting from DVD? They at least own part of BD so the gain, even if minimal is still a gain.
I can't be certain but I think Sony is finally making a profit on the PS3 so even if it's expensive it is still a bonus on top of a good gaming system.
