That spear doesn't look like it'd be useful unless you’re fighting off three vampires that were huddled together.
Sure it would. There are some variants of the real world brandistock that were like this; ones that were like a triangle pattern of three hooked spears and a good foot or two shorter than the average pike.
Lots of surface area means more laceration damage over direct penetration/stopping power, much like a shotgun would. Something like that with pronged points could also be considered a tripping weapon, as the three blades could easily snag clothing and mangle limbs on penetration, with the shorter handle providing aggressive leverage for pushing foes down.
I am mostly speaking out of my ass here but the end of the polearm appears to be a distinct piece from the rest. I assume that this means that the three points can be replaced/repaired as needed. I could imagine the pieces, if they were damaged, may possible be embedded in the target. Probably not the best as far as repeated usage is concerned, but if this a hunting weapon it may be a good tool against game.