Bitcoin benefits as opposed to fiat currency:

Very very low fees of transaction and storage - Millions of dollars transfered that require no fee or as low as a few cents
Not necessary to deal with banks, lawyers and regulatory agencies - a phone or PC and an internet connection will do; though some countries are beginning to draw up legislation concerning Bitcoin possession
The system is extremely hard to breach, thus uncommonly safe - due to the mathematical algorythms that transaction and Bitcoin creation is based (google Bitcoin mining)
Non-inflationary currency - unlike the Dollar, Euro or Pound which can and is printed out of thin air by governments and thus decline in value (phenomenon called inflation), Bitcoin is limited in possible quantity that can be ‘mined’ much like gold
Anonymity - although it functions on a ‘public universal ledger’ (the Blockchain) there is no way for any authority to find out who posesses and transfers Bitcoin; which has led to popularity for some unfortunate uses such as drug dealing
is not politically or geographically limited - universal use of Bitcoin would diminish fees for converting currency and there is no one political entity in control, rather it is based on open source code