Everything that people doing with gold or bitcoin just because of profit. They are usually saving their money by investing in gold or trying to get profit buying bitcoin.
That is obvious. Why would someone invest on something without himself, profiting on what that people are doing? If he is not getting anything into that, that means he is just wasting his money and his time. Putting it simply, people invest on Gold and on Bitcoin so they can earn good profit in the future when the price is right to sell it.