[@Ryougu] Basically. The Digivices have enough power to cross the dimensional barrier by themselves, but not enough to take a person with them. They need more power, and since they come from the Digital World, a computer is the perfect conduit.

[@SleepingSilence] I'd prefer if it wasn't instantaneous, but just remember that the Digimon have no idea who you are. You're just as unknown to them as they are to you.