This is a weird power grab from the court. Chevron already allows that the courts can decide what Congressional intent it. The deference to agencies only comes once they determine the law is ambiguous. In a different world, where we had expert courts full of engineers and analysts, this might even produce better results than the current system, but we do not, and Judges opining on technical fields are probably the only thing worse than engineers opining on the use of language, LOL.
I suppose if Trump wins and guts the career professionals in the executive branch and replaces them with partisan hacks at every level, we could end up glad this ruling happened, but agencies already had to act with a certain respect for internal rules and “reasonableness”. What’s more likely is that this SCOTUS will make sure it passes the final word on every significant regulatory question that arises in the next 20 years, and somehow magically the status quo that was being abused will become the law, even when it has only the thinnest threads of non-technical justification. Or worse, everything is now up for re-litigation and nobody knows WTF anything will mean anymore.