Do you know that ethereal prismatic highlighter that looks like you've been kissed by a rainbow? Well, this is not that highlighter. Etude House's description of their Secret Beam Highlighter states that 'this 6-coloured all-over baked shimmer powder in pearly white tone instantly enhances the complexion with a soft, youthful luminosity'. Is that achieved? Yes. Is it a holy grail product? No.
You would apply it typically like any other highlighter, accenting your cheekbones and along the bridge of your nose to give yourself that faint dusting of butterfly scales. As with highlighters, a light hand is recommended but the effect that this gives is very subtle. I find that the product itself in its pastel glory is a feast for the eyes but applied, it doesn't really carry over, unfortunately.
The conclusion here is that if you were building your makeup arsenal from scratch and this happened to be by your fingertips... that's the only outcome I'd envision that you'd pick it up since there are better products on the market. Although, how many highlighters does one truly need anyway?