The difference in the two types of downloads is that with the World of Warcraft downloadable version you have only ten days of free game play. With the World of Warcraft CD-key you get 30 days of free game play. What you are in essence purchasing is the World of Warcraft CD-key.
By doing this you are buying yourself extended time on a World of Warcraft server and you can take your time in deciding whether or not you want to go ahead and buy the game and create a proper account.
Account activation with the World of Warcraft CD-key in most cases is very fast and depending on the site which is selling these CD-keys, you will either receive them through the email, or in the post.
And normally after your World of Warcraft CD-key purchased time has ended you will then need to purchase an additional game time World of Warcraft CD-key. This will normally give you a set number of hours to log on and play the World of Warcraft game. To do this however, you will require a legitimate World of Warcraft account.
There are many reasons why a person would go to the lengths of purchasing a World of Warcraft CD-key but these are mostly centered around the fact that they’re still not sold on the idea of Warcraft as a great MMORPG.
For those of us who have played other Warcraft games, World of Warcraft is but another step up the ladder of Warcraft game playing, which The Burning Crusade expansion pack takes even further.
Use of a World of Warcraft CD-key and game time cards are also good for people who love to play World of Warcraft but who don’t have the time to devote to playing the game almost 24/7. For these people a proper account could become a burden, whereas a World of Warcraft CD-key activated guest account would be more helpful.
One large drawback with a World of Warcraft CD-key is the fact that you need to have the activation key with you at all times when you want to play. You would do very good not to loose it or put in a “safe” place as you will find that you need to buy a new World of Warcraft CD-key.