Now, try to use your browser's back button to return.
Can you use it?
The back-button is reportedly the most frequently used button in browsers — but it won't work here, because this window is new. Newly opened, this window does not have a "history" yet. It does not have a page in its own history to go back to.
Imagine the plight of a normal person on the internet, a casual surfer, who tries to use the back button, trying to return to the previous page.