To illustrate the need for backing, one must first understand why gold itself needs no backing. Gold doesn't need backing, because it has so called "intrinsic value". However, intrinsic value itself is contradictory, because when goldbugs mention intrinsic value, they mean to imply that intrinsic value is value that can be objectively determined and is thus value that can NEVER be stripped away. Hence, this is why gold needs no backing (according to them).

The notion that intrinsic value can be objectively determined is conflating two issues, namely that of intrinsic PROPERTIES and intrinsic VALUE. Intrinsic properties can indeed be objectively determined and much of the intrinsic value that gold has is derived from its intrinsic properties. Even if the entire human species dies out today, the intrinsic properties of gold will always remain. However, if the human species dies out, gold will automatically lose all its value, because only humans can determine value. Hence, ALL value is subjective in nature. There's no such thing as objective value (= intrinsic value). It's a MYTH.

Thus, gold is also subjectively valued. What people call intrinsic value is merely subjective value that is extremely hard to strip away. Why does gold nonetheless have such strong subjective value? Because it has UTILITY under the most diverse circumstances and it has proven that it has the ability to retain this utility over a span of 5000 years. Even so, it's still possible for gold to lose its intrinsic value. If I dropped an atomic bomb on the entire gold supply, it would lose any intrinsic value it had (thus demonstrating that there's no such thing as value that cannot be stripped away). However, the scenarios under which gold can lose its utility are extremely unlikely and it's because of LOW PROBABILITY of these scenarios that gold itself needs no backing.

So does Bitcoin need backing? Depends on the probabilities of the scenarios that Bitcoin can lose its utility. Bitcoin has MASSIVE utility greater than gold and it's this utility that gives it its so called intrinsic value (which is subjective value that is extremely hard to strip away according to my new definition). Some examples that can compromise Bitcoin's utility: 51% attack, encryption hacked, electricty/internet down for extended periods of time, governments banning bitcoin, fatal bugs. IMO, each of these scenarios are unlikely, but they are still far more likely than someone dropping an atomic bomb on the entire gold supply. IMO, gold still wins as a secure store of value because of this (the only place gold can compete with bitcoin), but as technology progresses, the security and robustness of bitcoin (or another alternate currency) to survive under any known circumstances will be improved that the scenarios under which it can fail will be as remote as the scenarios under which gold can fail. Should crypto gain this amount of security, it will wipe the floor with any existing asset, including gold. Gold will then be permanently supplanted as the number one store of value and the death of government currencies is then pretty much a matter of time.