Why even have video game versions of these games, you ask? Well...
1) These things set up the matches automatically without the mess of shuffling one's deck and arranging a battle space.
2) The rules of the game and abilities are kept track of, leaving human error out of the mix.
3) You don't have to spend ginormous amounts of money on the physical cards.
4) You don't have to have friends to play the game with other people. Because who needs friends nowadays?
5) In later installments, battles can be arranged over Wi-Fi with available players worldwide.
6) I guess there are also exclusive cards that can only be collected by buying the video games, if you're into that kind of thing.
Card Battle Video Games
Magic the Gathering Video Games
Electronic Card Collecting Games MtG