Why dont know everyone wanted Bitcoin to replace anything like bitcoin replacing fiat currency, or bitcoin replacing gold. When every one knows that Bitcoin is more like a good investment option just like gold and both investment option are good for investment as their price fluctuation is high.
Gold is does not have that high fluctuation on the price because it is more likely for long term investment which is good for people who want to have a secured investment. Bitcoin is just for people who want to make money in either short or long term or to be involved in the latest technology of the currencies and that is all about bitcoin and other cryptocurrencies.