I am fairly convinced that the causality is the opposite of what you describe. Sure, price and number of Google searches are correlated but correlation does not imply causation. It is rising prices that drive interest, not the other way around.
You have to be careful with what you think you're looking at too. You might think that interest in bitcoins correlates with Google trends but the thing is that the differential of an exponential is an exponential. Thus the trend on google may not correlate with the interest in something but rather with the *change* in interest in something but during an exponential period, these would look the same/similar.
