Yep.  It's teaching your thinking to be as efficient as possible.  Muscle memory is useful for this, as is removing distraction and interference from thought processes, prioritising information, remaining clear-headed.

...yeah, or performance-enhancing drugs.

Also, people learn and process new information in very different ways.  All this "practice" you're thinking about would only work if you're a kinaesthetic learner, who learns by doing.  I remember learning all this when I was an instructor, people have markedly different learning styles and with anything, you'll only benefit if you adjust your teaching to their learning method. 

Kinaesthetic learners need to do things, and adjust their muscle memory etc by repeated movements. You might be a visual learner or a book-led learner where studying the maps and reading about tactics might help, or watching videos etc.  Auditory learners might need to play the game with a coach telling them what to do.

You can practice single events to increase muscle responsiveness and situational reaction time, but not really much to do in the way of increasing your base reaction time.  Like people have said it's about processing the situation and then selecting a course of action, then your reaction time comes into play to action that choice.

Anyway, have a think about how you like to learn.  If someone was teaching you something at school, do you prefer to do it?  Watch them do it?  Read a textbook?  Or listen to someone describe it?