It was non-zero but close to zero.
Companies don't want to deal with the headache for many things. It's not a given over what time horizon and how much work is involved to get the refund. It's totally sensible to sell the claim for 70 cents on the dollar for example.
The supreme court absolutely hears cases that are obvious. They do it for several reasons - to create clarity, to narrow scope, to set a very clear precedent, and other reasons.
It wasn’t “close to zero.” The Supreme Court split 6-3, with two Trump appointees voting against him. And the Federal Circuit, which is the most boring appellate court and not political at all, split 7-4, with two democratic appointees and two republican appointees voting to uphold the tariffs.
This was a case that split both the liberal and conservative blocs. Obama’s former SG, Neal Katyal, went up there and argued for limiting presidential power over the economy. One of the justices quipped about the irony of Katyal’s major contribution to jurisprudence being revitalization of non-delegation doctrine, which has always been a conservative focus.