From the article: "The result does not unite quantum mechanics and gravity, nor does it show that gravity itself is quantum".
I must say, it's actually quite refreshing to read an article about a science topic that conveys the caveats and limitations of the study. Far too many of these studies get filtered through the news outlet hype-machine
If you'd learn about a proposed experiment to test the quantum nature of gravity, this is a cool video:
https://www.youtube.com/watch?v=Uey_mUy1vN0
Hopefully we'll see a result in the next decade