I agree lotus Noctus. I ll push the logic even further: my view is that Larian would choose fluidity/ease of access over perfect implementation because a. Wider audience and b. One thing less to implement.
As such if we want to have more reaction and more dnd 5e implementation we need to find things that are not requiring a large effort from a non dnd player and that would not alter the combat flow. Overwatch tick these boxes. I just wish we could find something for defensive spell (e.g. shield or silence)