Contrary to what you may think or have heard, there is no such thing as muscle memory. It’s a neural pathway in the the brain. When you change your swing, you have to build a new pathway.
Sounds like semantics, but it’s a huge distinction.
If muscle memory existed, you could shotgun balls as fast as you wanted and the muscles would groove the repetitive motion. However, since muscle memory doesn’t exist, your brain needs time to absorb all the information of each individual shot.
You have to organize where the ball went, where on the face it hit, how much it curved, how high it went, how much of a divot you took, where your left scapula was at P4.5, where your right patella was at P5.1….and on and on.
Your brain can process all this information and more, and build a block of information of both good and bad.
This is why hitting balls quickly is just minor exercise and has no benefit to your game.