Historically, tariffs had the purpose of protecting home industry against foreign competition. For example, 150 years ago, America had a big textile industry and had tariffs in place to force up the price of foreign textiles so they would not be cheaper to buy than American made.
Today, though, take a trip through the
industrial rust belt and visit the American factories that make all the stuff we import from China. Can't find them? Me, neither.
So, as far as I can tell, tariffs are really just a tax, and their main effect would be to act as a brake on the economy, which isn't something we likely need.