Nothing is instantaneous, but the less the lag time the better for many things, especially cameras.
We have our own built in lag time timing our shots. It’s that time from seeing the shot, to thinking it’s worth shooting to telling your digits to get busy to actually taking the shot. There’s a lot of stuff going on. Quite a chain of events.
The last thing we need is a camera that takes its time actually taking the photo. Just push and play!