I originally bought (yes, bought) Fortnite because a friend and I were super into H1Z1 (now the non-existent “Just Survive” version, RIP) and he thought they would be similar. They certainly weren’t identical, but there was definitely some overlap.
Then PUBG started to get popular and both H1Z1 and Fortnite completely redesigned themselves … One more successfully than the other.
Not defending the decision. I think it’s bad design.
That said, supposedly the reason is that the doorframes do not run along the top of the window, allegedly to reduce the weight of the car. Because of this, the window itself has to form the seal, which could potentially damage the window if the door is mechanically opened. The electronic button lowers the window as it opens the door in order to reduce the risk.
Again, I don’t support this reasoning. I’m just sharing it.