These things protect against one part of the problem - deletion of the vector, but not the other part - mutation of the vector, causing a new internal allocation, and leaving references to any elements of the previous vector invalid.
It's possible to make sure this isn't happening in C++ if a) your code base is small enough and b) you are careful, but the point of the article is that with Rust, you can make the changes and be confident that the compiler will fail if you do anything dangerous.
With C++, you can make the changes and through careful checking be reasonably confident everything works (perhaps only to find out later that you were wrong). It's very different from having the compiler verify that you are not doing something unsafe.
These things protect against one part of the problem - deletion of the vector, but not the other part - mutation of the vector, causing a new internal allocation, and leaving references to any elements of the previous vector invalid.
It's possible to make sure this isn't happening in C++ if a) your code base is small enough and b) you are careful, but the point of the article is that with Rust, you can make the changes and be confident that the compiler will fail if you do anything dangerous.
With C++, you can make the changes and through careful checking be reasonably confident everything works (perhaps only to find out later that you were wrong). It's very different from having the compiler verify that you are not doing something unsafe.