Binary Search-accessing the middle element drawback
It seems that author compares array-like structures  and linked list
The first (array, Python and Java list, C++ vector) allows fast and simple access to any element by index, but appending, inserting or deletion might cause memory redistribution.
For the second we cannot address i-th element directly, we need to traverse list from the beginning, but when we have element -  we can insert or delete quickly.
I am studying from my course book on Data Structures by Seymour Lipschutz and I have come across a point I don’t fully understand..

Binary Search Algorithm assumes that one has direct access to middle element in the list. This means that the list must be stored in some typeof linear array.

I read this and also recognised that in Python you can have access to the middle element at all times. Then the book goes onto say:

Unfortunately, inserting an element in an array requires elements to be moved down the list, and deleting an element from an array requires element to be moved up the list.

How is this a Drawback ?
Won’t we still be able to access the middle element by dividing the length of array by 2?