Learning Transfer

Anything outside of a field that is said to be unuseful to learn is false.

"Does taking economics help when I am studying for architecture?"

You do not necessarily need to take economics when pursuing architecture but it can help you by transfer of learning. 

Considering economics that studies the idea of input and output relationship, it helps you to think in a contextual manner that broadens your understanding and design languages in design. 

Also, the notion of production and consumption is very much similar to the subset of architecture which is in the form of human behavior, culture, and the manifestation of its effect in a place.

(Read: The Practice of Everyday Life by Michel De Certeau

After all, everything is connected to everything else.