It comes with a balance knob?!?! I'll take it!

...said no one ever! I've been researching new gear and it hit me. Why, just why, do pieces have a balance knob? The only time in my life I can remember using said knob was to mess with the music and irritate my friends. You know, because it was cool to make every song sound like that classic Led Zep track. I think it was the 80's and on my Sanyo "boom box".

What is the point? To look retro? Do people actually use it and why?

Thought this might be fun to discuss and learn something new.