Coiled pins were designed with assembly in mind. Compared to other pins, their square ends, concentric chamfers, and lower insertion forces make them ideal for easy installation. Additionally, coiled pins can accommodate wider hole tolerances than any other pin because they compress during installation and conform to the shape of the hole. All in all, coiled pins are the easiest type of pin to install and are designed to be serviceable.(…)
via How to install a coiled spring pin | Fastener + Fixing Magazine.