is one piece episode 870 filler?

After being beaten into the ground by Katakuri, Luffy moves to end the fight and activates a form of Gear 4 known as Snakeman. During his training on Rusukaina, Luffy had shown the abilities of his Boundman form to Rayleigh.

However, Rayleigh questioned how effective it was as he hit Luffy with great speed and used his Observation Haki to dodge Luffy's attacks. Upon entering Snakeman in the present, Luffy throws a punch straight at Katakuri, who dodges it and is confused about why Luffy seemingly initiated a simple attack.

However, the punch then comes and hits Katakuri in the side.