Knowing Ayu, she tends to do things to a very exagerated degree, so the overly cute/sexual Ayu's featured in the PV make sense to me.
It's also could be interpreted as a critique of not only shy/idle people, like the lyrics suggest, but also how artists in Japan over use the cute/innocent image, especially since it's so classic in the pop scene. Especially among new artists. Maybe it's trying to say how it won't get you anywhere just being cute, you have to be bold and take risks.
Or maybe I should just ***** about how I was expecting a much "darker" PV because SPARKLE (lmao, not even the tittle is dark), is SUCH a "dark" song. My bad.