Even gold isn't backed up by anything, right?

So why do people trust it and want to pay with expensive value? Because people believe Gold is valuable. The main thing here is people's trust. It is the same as Bitcoin, it doesn't need to be backed up by something because people trust it. People believe Bitcoin is something valuable and useful for human life. In this matter, something like Gold and Bitcoin is acceptable although it is not guaranteed by anything.
Bitcoin is software. Gold is an element that cannot be created by man. It has to be mined. And obviously there is a limited supply of it available here on earth. Gold is a precious metal that has many applications and uses. Bitcoin is just software. You can copy software and rename it. You can't do that with gold.
Anyone with particular knowledge can create cryptocurrency. But not anyone can produce gold because it is an natural mineral resource that has limited supply. While this is true, it should also be noted that bitcoin can't just be reproduced easily by copying and renaming. It doesn't work that way. If you will insist on doing so, you will definitely not succeed in renaming it alone. You can do another crypto coin, but it isn't guaranteed that it will be as valuable as bitcoin.
Remember, there are many crypto coins now circulating in the market, but not everyone has a value. Not everyone of it have the potential to rise up or surpass bitcoin too. Because without patronage, a crypto coin is useless.
although bitcoin is really just software and only works when there is an internet connection, but look back 13 years, many altcoins have been created and have you seen one that is similar to bitcoin or is there any better than bitcoin that you have seen?
whatever it is, their value will be determined by people's beliefs, once we lose faith in it, they will become useless
gold is no exception, its value is also determined by people's beliefs