This will put the blocks to the enormous “gray market”, where products that are expensive in the US are made in other countries for sale at much lower prices, then shipped to the US.
Because they are licensed, they are not illegal. A good example are Criterion DVDs and BRs. They retail in the US for high prices, but when (licensed) manufactured in South East Asia, they sell for much lower prices for the local market.
So people there will buy them up, and sell them on sites like eBay. At perhaps a third of US retail. They took advantage of the “de minimis” customs and postage to ship to the US cheaply.
You are on the right track.
Cuban cigar shipments from Europe and Asia have been stopped this week—for the first time since the Cuban embargo began under JFK.
The US was 20% of the international market—even though the product is illegal in the US.
The vendors are not primarily worried about tariffs. They are concerned that customs will carefully inspect a much larger percentage of packages and will confiscate the contraband.
(I have a lifetime supply already—another “gloom and doom” theory becomes “gloom and doom” fact.)