There’s no conceivable drawback to regularly practicing without automation. My first jet didn’t have autothrust. I quickly had to learn power settings for different phases and configurations. Eventually you get to the point where you can set the approximate power setting without even looking at the engine instruments- your hand just knows where to go.
Likewise with pitch. If for some reason the attitude indicator doesn’t look just so, you know it’s not right and you fix it.
That sort of intimate knowledge of the aircraft comes in handy in an emergency. The flying part becomes subconscious. You’re using your mental capacity to handle the emergency. If that means I don’t fly the ILS as crisply as the AP in good weather, so be it.