Why a technical reason? Maybe it's a deliberate design decision, like how the physics are set up in a video game. Maybe in this sort of scenario, they did som

Why a technical reason? Maybe it's a deliberate design decision, like how the physics are set up in a video game. Maybe in this sort of scenario, they did some playtesting and found that setting light to that speed made the game more 'enjoyable'. Then again, it could be a way to cover up for a lack of content. Set the speed of light to be faster, and it might theoretically make it so a species with massively advanced technology could reach the edge of the universe. More convenient and realistic than an invisible wall.