As an example, say ETH is the world's main medium of exchange. Everything is measured in terms of ETH, whether that's your weekly salary, the price of food or a computer. And you need ETH to buy literal gas to get to the market, or to the computer store.
Now imagine if nobody wanted to use their ETH, and preferred instead to keep them stored in their wallets. Since the value of everything gravitates in relation to ETH, there would need to be something out there that is 'interchangeable' with ETH, so that even if all the ETH in the world were kept in wallets, people could continue to transact freely.
Knowing that whatever they received would be able to be traded in for ETH at whatever point in time they so desired. That's what $GAUR hopes to become for $ETH in 1000:1 ratio, meaning that 1000 GAUR would equal 1 ETH.