Activision/Blizzard uses its own platform for their PC games. As with Steam and Origin, you need to download a client (Battle.net) and create a Blizzard account. If your game needs Battle.net, you can see in the product description under the entry "Delivery".
At Gamesplanet you can activate your purchased game directly into your Blizzard account. Keys will no longer be delivered. Just click and the game is yours!
Yes you can! At Gamesplanet you can choose to gift your entire order to another account, or claim it on your own account. After purchase you'll be given the option to make your purchase a Gift Link or you can redeem it on your own Battle.net account. Find out more details about How Gifting Works or reach out to us if you're still not sure.
You can find more information about Battle.net and how to contact Blizzard customer support at: Blizzard Support