They are designed to quickly frame houses, not be durable furniture.
Can confirm: this stuff is way harder than the studs are. I used the same size pilot hole that I used in the wall studs, and it sheared the heads right off the deck screws.
Confirmed! Hard maple! In regards to its hardness, they actually use it for bowling alley lanes so it’s some pretty durable, dimensionally stable, easy to work with stuff! And pretty cheap! 4-5$ per BF