What is the significance of trade? Why oh why does it occur? (What i know is that 2 parties gain more if they trade but is there anything else? i feel i missed something...)

Question

Fundamentally, that's it. With trade, both parties are better off.

Now then, the existance of trade leads to specialization. This improves overall productivity.

The existance of trade also leads to markets. With markets, economists can measure the relative value of goods and services.