Either his tariffs would be upheld, which would be good for the U.S. because the tariffs are good,
or,
The Court would determine that Congress inappropriately attempted to pass constitutional congressional powers to the President, which I always suspected to be the case, and a constitutional clarification in this regard is also good. And, this could have ramifications for other congressional powers Congress attempted to transfer to the executive branch. The Left may come to dislike such limitations.
Of course, as far as tariffs are concerned, unless one of the other justifications for tariffs is upheld, it would mean that tariffs are dead as a concept, since Congress will never pass tariffs going forward, just like Congress will likely never declare war going forward.