[guide] Update reason for preferring object destructuring

Fixes #2293

The reason for preferring object destructuring is quite narrow in scope. While this guide isn't intended to provide every possible reason for every preference, it perhaps should aim to provide a succinct and compelling reason. The current reasoning could be improved to meet this standard, so I'm proposing adding some additional information to clarify the benefits of what is an often controversial rule (controversial only because its introduction can require many changes in a mature codebase and has no auto fix available).

README.md

@@ -497,7 +497,7 @@ Other Style Guides
   <a name="destructuring--object"></a><a name="5.1"></a>
   - [5.1](#destructuring--object) Use object destructuring when accessing and using multiple properties of an object. eslint: [`prefer-destructuring`](https://eslint.org/docs/rules/prefer-destructuring)
 
-    > Why? Destructuring saves you from creating temporary references for those properties.
+    > Why? Destructuring saves you from creating temporary references for those properties, and from repetitive access of the object. Repeating object access creates more repetitive code, requires more reading, and creates more opportunities for mistakes. Destructuring objects also provides a single site of definition of the object structure that is used in the block, rather than requiring reading the entire block to determine what is used.
 
     ```javascript
     // bad