Ortholinear isn't necessarily better. I have a Plank collecting dust in my drawer. These designs are not anatomically better shaped than the standard staggered keyboard.
An ortholinear split keyboard is better (it's easier to rotate either half without the normal key stagger getting awkward), but I don't see any reason to buy a Plank.
I have two Ergodashes [1], one for home and one for the office.
It's also not going to increase typing speed. Learning to touch-type can do that, but 99% of the gain from changing the physical keyboard layout (ortholinear / split etc) or logical keyboard layout (Dvorak, Coleman etc) are for typing comfort.
Of course, a split keyboard with offset columns is something else. The parent comment specifically mentioned Preonic and OLKB. As for the Plank, the claim is that it reduces finger movements, but in reality it is just cramped and puts your writs and fingers in an awkward position. The only thing I liked about it is the layers, but then getting used to that just threw me off when using the standard layout.
I have a Planck EZ. Thought it would make me faster since num pads are linear and I'm super fast on those. However, it's the switching between staggered and linear really dragged me down.