Nether brick blocks no longer craft able:: recipe crafts a single nether brick, so you use 4 nether bricks to them craft a single nether brick instead of a nether brick block.

So I smelt nether rack to get nether bricks, and when I use the nether bricks to craft nether brick block, the nether brick block is not made, instead a single nether brick is crafted. So it's just wasting nether bricks lol