According to the New York Times, this was a very narrow majority on a key 4th Amendment issue. The majority opinion hinged on deeming a cell phone to be qualitatively and quantitatively different from closed containers, the standard to which the prosecutor was trying to hold the defendant’s cell phone.
The prosecutor was clearly not pleased, trying to paint this as an untenable form of technology based exceptionalism. That being said, he hasn’t decided whether or not he will appeal the decision to the Supreme Court.
I tend to think the court got this mostly right, not just given the vast amount of personal data potentially stored on a phone. Increasingly, phones are also edge devices that store credentials to even more information out on the network. I don’t think that was the case here, but the line is increasingly blurred. Pursuing a search through the device onto online spaces would clearly take it much more into the contentious grounds of online surveillance and access to third party information, not just rifling through seized personal effects.