Further clarification on the benefits of passing in immutable slices to functions

Author: mckzm

en/src/collections/vector.md

@@ -113,7 +113,7 @@ fn main() {
 ### Slicing
 Immutable or mutable slices of Vecs can be taken, using `&` or `&mut, respectively.
 
-In Rust, it’s more common to pass immutable slices as arguments rather than vectors when you just want to provide read access. The same goes for `String` and `&str`.
+In Rust, it’s more common to pass immutable slices as arguments rather than vectors when you just want to provide read access, as this is more flexible (no move) and efficient (no copy). The same goes for `String` and `&str`.
 
 5. 🌟🌟
 ```rust,editable