You're correct that it's a GA hack. Avoid it.
Google has publicly stated that they don't use your site-specific GA metrics to influence organic search rankings. E.g., they're not taking data from your GA profile, and feeding that to the Search Quality team to determine if your site should rank better or worse. They have MANY better ways to accurately track anonymous user interactions with sites at scale (e.g. Chrome).
The only thing that you'll accomplish with this code is making all of your own internal metrics turn to garbage. Accurate metrics are important. If you bounce rate is high, knowing that allows you to take action to improve your site and reduce it.
The more people who stay on your site for more than 1 pageview, the more money your business is likely to make. Improve your bounce rate to improve the profitability of your website, not for some supposed correlation between bounce rate and organic search ranking.