Bitcoin is just like any other digital currencies: nothing new!
Nearly all other digital currencies are centralized, and that means: can be printed, according to the personal will of whoever controls them;
can be destroyed by attacking the central point of control;
arbitrary rules may be imposed on their use, by who controls them.
Being decentralized, bitcoin solves these problems.
Bitcoin don't solve the problems they have traditional currencies and/or the gold!
Unlike gold, bitcoins are: easy to transfer;
easy to protect;
easy to verify;
easy to split.
Unlike traditional currencies, bitcoins are: predictable and limited in their supply;
not controlled by a central authority (e.g. the Fed or the ECB).
Unlike traditional currency systems, bitcoins are: potentially anonymous;
freeze-proof;
fastest transfer;
cheaper in the transfer.
Bitcoin is backed by processing power
It is not correct to say that bitcoin is supported by processing power: say that a currency is "supported" by something means it's anchored to something else, through a central organization and at an exchange rate determined. Instead, you can exchange bitcoin with the computing power used to create them. Bitcoin is, in this sense, not attached to anything. This is a currency in its own right. Similar to the gold ... and gold is supported by something? No! And "only gold. The same is true with bitcoin.
The currency in bitcoin is "created" thanks to processing power, and the integrity of the chain lock is "protected" from attacks thanks to the existence of an extensive network of computing nodes. And that's it.
Bitcoins are worthless because they are not supported by anything!
Even gold is not supported by anything. Bitcoins have intrinsic properties related