I have a collection of old wooden dolly pegs and tried using them but I always much preferred wooden spring pins.
In my experience, dolly pegs fail to secure washing to the line, they loosen easily, can easily damage items (vinyl/plastic/rubber things), and they break easily.
OMG, OMG, OMG, Milly, my dear SIL was babysitting for a neighbourhood mom and while changing one of the kids, she parked the diaper pins in the waterbed! Oops! Yes, she heard about it!