Another thread with Hackett trolling again like usual. (I just see a load of posts that say [Users do not think this post contributes.... ] with your name by it....)
Hackett; they made the game require a connection to blizzard at all times for many reasons. One of the main reasons is the auction house system. You are allowed to sell items that you find in single player on the auction house, and by doing so they want to control the items that drop server side when the game is played to attempt to enforce security over this system.
Another reason is that, like a cloud service, I can pick up my characters anywhere in the world with the D3 client installed by simply logging in.
These are the choices they have made. The second one isn't concrete grounds for always online but it's made easier that everything is stored server side with exception of the local cache.
Unless you sit on their board you cannot say for sure what all their intentions are and so speculating that the game requires an internet connection because they don't want to give you the game is just stupid and another one of your trolling sprees. Trololololololol is all you seem to say (at least the google translator can make sense of some of what you say for us).
As a reply to the DVD requirement; this is only required, as others have said, to install the game if you chose to install it from DVD. You can use your code to download the client if you don't have it. You can copy the client from someone elses machine if you like. There is no copy protection on the DVDs or the client itself, but it can only be distributed online under licence I believe; like a lot of things.
Just to add in guys, I'm not sure if this has been mentioned but you will not require the CD to play the game or even install the game. Yes, that's right, I did say "install".
Visit this Diablo III's official website. http://eu.battle.net/d3/en/blog/4410912/ - Check the website for other installers of your region.
Download the Diablo III installer that is in your region. Wait for it to download, it is 7.6GB's. You will only need the CD key that will be inside the retail copy, so you can activiate the game through Battlenet.
Speculative rubbish as usual Hackett. Show me documentation that this is the sole reason that they have made it online only and you have ignored my post that said there are many reasons including the ones I listed.