There is a mix of metric and non-metric products, with panel products having more than lumber. Occasionally you even run into other weird measuring systems such

There is a mix of metric and non-metric products, with panel products having more than lumber. Occasionally you even run into other weird measuring systems such as in traditional Japanese beams. North America seems very stuck in imperial measures when it comes to lumber specifically, likely due to entrenched skills and thinking in carpentry. Even PET (precision end trimmed) products designed for cookie-cutter construction are in inches (eg 140 and 5/8"). There is even resistance by old guys against metric threading on machines since all the old tooling and warehouse stock is imperial!