Bitcoin is a virtual currency that exists only digitally and can be purchased only online whereas gold is a physical assests that you can touch and hold. The difference between is currency part . Bitcoin is more volatile as compared with gold. Bitcoin is referred to as a gold. Both have their own importance on their own.
That is both relevant to each other as well. Bitcoin is virtual but in today's world too many things are virtual, you can hold gold if you want to in your hands but you could also buy gold from your bank account, it would show you owning 10 ounces of gold without ever touching any gold at all, it is just paper, same with fiat as well, you have money digitally, it is in your bank and you can use your credit card instead of actual money and hold the cash in your hands.
Overall, I would say that it is obvious people are using stuff virtually. BUT the fact that crypto is purely digital means it could be used to transact money, buy stuff, sell stuff, work, pay and so forth and that is the biggest difference.