The scaffolding planks are also easy to rearrange

Occasionally, the wood planks are doubled to give more support to heavy work materials such as brick and mortar. The overhanging ends of the planks also provide a place to set materials and supplies whereas the aluminum platforms stop directly at the edge of the scaffolding. Another reason that some workers often prefer the use of the planks over that of the aluminum platform is the tendency of the platform to stick to the scaffold. The platforms will sometimes become stuck if the scaffold has twisted or shifted in the least, requiring the platforms to be pried and pounded out of position at breakdown time, whereas the planks simply lift off of the sections.

The use of scaffolding planks not only saves time, but also saves money and typically offers the same safety as the purpose-built platforms. The scaffolding planks are also easy to rearrange while erecting the scaffolding, providing better or enhanced footing while straining to raise the scaffolding sections in place. In some situations, workers will actually equip the working section of a scaffold with both an aluminum platform and scaffolding planks. The job materials are often kept on the aluminum platform since it has sides which prevent the materials from accidentally falling off of the scaffold while the workers perform jobs from the scaffolding planks.
 http://www.shscaffolding.com/