Blanked Tariffs are seldom useful.

They’re useful as punitive measures. Taken to the extreme, sanctions, embargos, and such are - functionally - just very high price tarrifs.

There are political reasons for a country or confederacy to deliberately cordon off trade with a neighbor or global rival. Most notably, if you’re pursuing regime change or concerned over foreign intelligence services infiltrating through trade channels, you’ll deliverstely choke back trade.

For people who believe the whole world is against them, tariffs make a lot more sense.