>>2549476
2x4 are 1.5x3.5 typically because when they cut it at the mill they will then dry it, which causes it to contract. That’s where the half inch goes. It’s not any kind of deception and you do not gain anything from using a “true” 2x4. If you are using mostly 2x4s for your loadbearing elements, you already fucked up. 2x6s for loadbearing and exterior walls are standard. 2x4s mostly used for non-loadbearing walls, with some exception (ie garage walls, party walls).