Re: why can't bitcoin be based on something that has value?
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.
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.