Hopeton01 - Chimneys

I was drawn initially to the vibrant colours of this sunset sky across the road from where I live. But I decided the way I positioned the chimneys meant they ought to be more prominent - hence the Mono is my main and the colour is today's extra.

But can anyone tell me what chimneys are actually for these days?

The houses around here are no more than 20 years old, were built with central heating and the vast majority do not have an open fire, so what's the story?