Canada

Wood is much cheaper than concrete block, and is much faster to build with. A standard house wall, say 20ft long and 8 ft high (1 storey) would require approximately 20 2x6 and 4 sheets of plywood. Thats approximately $220 in materials at big box store prices (so much less for builders). In comparison, just the blocks for the cinder block wall (8"x16") are $900, plus mortar.

To cut studs, nail, raise the wall, and add plywood is a two man job for ~2-4hrs, assuming no windows or doors. That is easily a job for a few days if you use cinder blocks.