It's not a matter of a "lesser" fighting style, but rather incorporating the two styles into one.
Oda is making it pretty clear with Wano, the Samurai, Oden etc... That there is a distinction between those who are to be considered actual Swordsmen, and those who fight with a sword/weapon to compliment their already established fighting style.
It's always been apparent that there is a difference, otherwise Oda would never had needed to make characters (especially ones Zoro has faced) announce that they are Swordsmen. If everyone with a Sword is a swordsman, then announcing they are Swordsmen is redundant, and makes no sense.
Oda is making it pretty clear with Wano, the Samurai, Oden etc... That there is a distinction between those who are to be considered actual Swordsmen, and those who fight with a sword/weapon to compliment their already established fighting style.
It's always been apparent that there is a difference, otherwise Oda would never had needed to make characters (especially ones Zoro has faced) announce that they are Swordsmen. If everyone with a Sword is a swordsman, then announcing they are Swordsmen is redundant, and makes no sense.