They didn't just mention it. The explained that it means that they (the courts) interpret the law. That they decided Raimondo on statutory grounds (specifically the Administrative Procedures Act) doesn't mean that they wouldn't have decided it on constitutional grounds if statutory grounds weren't available. Basically they've left the door open for Congress to fine-tune things a bit, but if they try to enshrine Chevron in law then it's pretty clear that the majority on the court already doesn't think much of it.