What else do people need to know about gold? Perhaps they already have many of them in their vault
But they still dont know about bitcoin, that's why they search it

You've got a point there, of course bitcoin would obviously got the highest result because of the trend, plus normal people would not put their attention in a thing that they already knew, instead they will search for something that catches their attention and interest.
As crazy as it seems to be, it has and is becoming a reality. The survey conducted and results gotten shows that Bitcoin adoption is increasing and also adaption is being ignited. Google is the first to come to mind when people want to get information from the net. As a lot are coming into the Cryptocurrency world, they will definitely go in search of Cryptocurrency and Bitcoins. And bitcoins is a base Cryptocurrency of all the digital currencies.
Nobody cares about gold or silver anymore. They left physical assets and they know how beautiful virtual assets are. That's how they increased the number of bitcoin researches on Google.
That's right dude, they would not let the chance of making a higher profit pass by.