What's the point of pamphlets?

And does anyone actually read them?

I’ve been a keen poetry reader all my life, but one thing I still don’t quite get is the point of the ‘pamphlet’ (or ‘chapbook’). These are small collections typically of between 15 and 30 poems, not usually running to more than 40 pages, and generally — as ‘pamphlet’ suggests — simply stapled rather than bound. Publishing a pamphlet, either via open su…