Why do composers use symphony to express the world of human feelings?

A symphony is one of the few works where a huge number of different instruments are involved at the same time. And at the same time, each of them has its own timbre, its own specific sound, expressing a certain mood and conveying certain emotions of the composer.

The same thing happens with a person – a huge number of sensations are simultaneously intertwined in his soul, and the mood in which he is at the moment is a kind of resultant vector of all experienced feelings.