That was the older thinking. Turns out users know how to use the back button quite well, and don't expect or know how to return from the pop-ups target=_blank creates, it breaks the back button. In user testing they report they think they've clicked a spam link, and it hurt our conversions.
That's before the accessibility concerns, users don't expect pop-ups anymore and find this confusing and difficult to navigate.
Target _blank keeps the title of your page on the screen and clickable.