I do not expect Congress to atomically approve or disapprove every regulatory action. That is a straw man. I expect them to write clear laws that state what agencies can do, what they cannot do, and how they should do it.

The case before the court is a good example of how the opaque and unaccountable nature of a federal agency allows them to serve their own self-interest at the expense of the citizens they are supposed to protect. Specifically, Congress specified in law that "authorizes the government to require trained, professional observers on regulated fishing vessels". But their law did not specify who would pay for these observers. So under Chevron, the agency got to decide. And, shocker! They decided they did not have to pay for it.

This ruling stops that specific abuse, and hopefully many others. The actions of federal agencies is not generally a thing to be desired.