SEO is mostly the prediction of the peoples to get rank on Google. Because in reality Google never tells about their SEO in public. SEO is made by Google to detect fake websites or fake content, etc. If they tell everything about how they figure out those fake websites or contents then the faker will be so much smart and Google will not be able to find fake activities on the internet.
That is why nobody can't tell exactly how SEO works. But as that SEO advice was given by the expert bloggers or SEO freelancers somehow it maybe works. But as Google always changes its SEO methods we cannot say it will 100% work.
So for your answer, the Backlinks were important in the past but this is 2019, so nowadays Backlinks were at least important. But still, if you were able to create good backlinks then it is good for you.
To know more about how to get a higher rank on Google and to know more about the present 2019 SEO factors click here SEO Ranking Factors.