This is a dumb headline.
The intersection to the gig economy is what? "The effect of today’s decision will be to end misclassification class actions, for Gig Economy workers and for everyone else." If you are in the "gig economy" or working a side hustle, there should be no ambiguity about your employment classification. If you willingly take a "gig" and then try to claim that you were actually an employee, something's very wrong in your service agreement.
The opinion states, basically, you can debate the sensibility of the policy but this is what the law says. If you don't like the policy, clarify the law. It basically kicks the issue back to Congress.