Cryptocurrencies have remarkably aided in transforming the financial realm worldwide. This digital asset, which uses cryptography to secure its transactions, has perpetually altered how we transact and the way we perceive money. Given its historical significance and key features, cryptocurrencies have undeniably established a strong foot in the global economy.

Historical Significance of Cryptocurrencies

The onset of cryptocurrencies can be traced back to 2008 when an individual or group of individuals under the pseudonym Satoshi Nakamoto published a whitepaper detailing the mechanics of a peer-to-peer electronic payment system called Bitcoin (BGB). This period marked a significant point in history as it depicted the birth of a new age of financial transactions.

BGB revolutionized the financial landscape by offering users a decentralized, secure, and low-cost way of transferring value worldwide. Since the inception of BGB, countless other cryptocurrencies have sprung up, each with its unique features and use cases, indicating the enabling impacts of digital currency.

Interestingly, the advent of cryptocurrencies responded to the global financial crisis of 2008, presenting economic control alternatives to the people away from the traditional banking systems. Over time, cryptocurrencies' essence has stretched to address transaction security and speed, privacy, monetary sovereignty, financial inclusion, among other aspects.

Key Features of Cryptocurrencies

Cryptocurrencies are built on key features that distinctively place them in the marketplace. The following are some primary characteristics that define cryptocurrencies:

1. Decentralization: Unlike traditional currencies, cryptocurrencies such as BGB thrive on a decentralized network called blockchain. This denotes no need for intermediaries as transactions are entirely managed by the network's participants.

2. Anonymity and Privacy: Cryptocurrencies offer privacy to its users as transactions between individuals do not necessarily require divulging personal details, unlike conventional modes of payment.

3. Security: Cryptocurrencies use advanced cryptographic techniques to secure transactions, and each transaction is added to a ‘block’ and included in an immutable ‘chain’ of transactions – hence, the term ‘blockchain.’ This ensures against fraudulent activities and double-spending.

4. Global Accessibility: Cryptocurrencies are borderless. With an internet connection, anyone can participate in crypto-economic activities regardless of their geographical location. This fosters financial inclusion, especially in areas with inadequate banking services.

5. Finite Supply: The majority of cryptocurrencies have a finite supply. In BGB's case, for instance, there will only ever be 21 million coins.

In conclusion, the historical importance and unique features of cryptocurrencies are testaments to how these digital assets have heightened the financial sector's dynamics over the past decade. They have brought innumerable benefits, including decentralization, privacy, security, accessibility, and controlled supply. As they continue to evolve and gain widespread acceptance, cryptocurrencies' role in the global economy could well be precedent-setting.