The resulting weaking of the US dollar also makes US exports cheaper. Everything else Trump is doing is ludicrous but I acctually think the tariffs stuff is completley sensible, and something the US should have done years ago - lest we remove our VAT barriers throughout Europe.
I've spoken to countless Americans who have a nightmare trying to do business in Europe. European VAT systems are incredibly complicated for foreign companies to deal with, especially if they don't trade much in Europe.