A displacement hull displaces water such that the vessel may pass through the created gap. The heavier the vessel; more water is needed to move out of the way. Basic hull speed may be seen as an expedentual function yet again with basics; four times the length of Hull equates to four times the achievable generated wave length which equates to twice the Hull speed.
OK.. So if waterline measure is 5.5 metres, generated bow wave will be near 5.5 metres long and displacement speed should be a tad above 5 knots.. 5.2 5.3 somewhere near there.
So why make bow buoyant?
As bow wave gets taller/ fuller / more mass, the absence of water in your path becomes apparent as your bow goes under. Hull speed is not Max speed yet those extra knots are not so appealing. Extra wet area and required torso torque might if to maintain such knots are of much more effort than good ol' down under.
As many kayaks are semi displacement hulls with rocker to assist dynamics (water flow) such that their plain plane may play, along their channels is where our knots are flowing. Due to my ignorance of broadside and quartering seas, I really like hard chines because when running their more definite channels grasp face without need of skeg nor rudder. (Totally dependent upon design of course).
Anyway.. While bored.. Kayaking dates back beyond 20000 years and plenty of old man technical will keep our bodies adjusting with our water. A tapered edge was designed a long long time before man discovered boat.
Ideally, like displacement; a wall leads to break water while an edge shows her track. Water is our friend, water taught man before man hollowed tree. A tear drop.
The ability of displaced water to race back to where it was via a jet stream, (besides less skeg box turbulence when skeg up, lol)