So what do they have in common. The fly fisher carefully selects the fly, the spot, the time of day, using a select rod, and has great skill and attention. On the other hand the fisher who wants lots and now, takes a piece of dynamite out in a boat, sets it off, gathers lots of fish.
The Tariff issue is the same. One could look at every country, every trade, consider the positives and negatives then propose something to a Committee. Or, you could just thrown a piece of dynamite and get the answers real quick!