Yep, it's an actual thing. I mean, we use psychic powers in the Reaper's Game, so it makes sense why fashion would be armor for the brain. And the more confident you are in your style, the more power it can give you. I like to think it's one of the one things that'd still work... I mean, Koishi's mask kept a bit of its hope powers, so why wouldn't your eyepatch? Even if you just think of it like a lucky charm.

[He doesn't know what 'the placebo effect' is called.]