Something else not mentioned is people's various anthropometries. If you have a barrel chest and short t-rex arms, you're probably going to bench more than floor press. In fact, there are some people on a floor press who will touch their chest before their arms reach the ground.
If you have normal to long arms and normal to slender chest, there's a good chance you'll floor press more.
Now if you can 3-board press more than you can bench press, that doesn't mean your chest is the weak point. It just means you have better leverage.
What I personally like about the floor press is that it takes away leg and lat drive so I can focus on the chest, shoulders, and tris. It's also a lot friendlier to my joints.