It does effect his game. There's actually no way it doesn't.
Two things to think about:
1. His hair extends into his peripheral vision. No matter what he has an unnecessary blind spot. When he's at rest he only loses a small portion off the top of his circle of vision. However, when he's in motion the hair bobs up and down cutting deeper into the circle. Sometimes going over half way.
2. I noticed he compensates by tilting his head back so he can increase his vision. He's doing himself harm by trying to play an elite game this way. It isn't natural to hold your head in that position. He also appears to have a nervous twitch with his neck on D. I would guess the hair has everything to do with that.
Therefore, he's sacrificing his lower peripheral to adjust for the upper. Also, a shot is a very delicate thing. Every centimeter of alteration matters to an elite shooter. Steph is absolutely exceptional at maintaining pure form. For a guy like Elfrid, a rough shooter, he can't afford to have any added obstacles.
A kid who wants to express himself can do whatever he wants. It's a free country, thank the Lord. However, a humble professional who wants to be the very best will sacrifice personal style to increase his game even if it's only fraction of gain. (Ie. swimmers shave their legs).