Yes. Bitcoin has not been made illegal in any country to date, although some nations restrict its use more heavily than others. Bitcoin is often associated with crime, because it can be used to make criminal transactions. However, this is true of any currency. Bitcoin is harder for authorities to trace than digital fiat transfers, but easier to trace than cash, and most criminal transactions in the world are made with fiat, not Bitcoin.
In January 2015, the company received a US$75 million investment, led by Draper Fisher Jurvetson, the New York Stock Exchange, USAA, and several banks. Later in January, the company launched a U.S.-based bitcoin exchange for professional traders called Coinbase Exchange. Coinbase began to offer services in Canada in 2015, but in July 2016, Coinbase announced it would halt services in August after the closure of their Canadian online payments service provider Vogogo.
In the case of Bitcoin, miners run computer programs to verify the data that creates a complete transaction history of all Bitcoin. A technology known as the blockchain, which is used to create irreversible and traceable transactions, makes the process of verification possible. Once a miner has verified the data (which comes in a block, hence, blockchain), they are rewarded with some amount of digital currency, the same currency for which they were verifying the transaction history. So mining Bitcoin, for example, would earn you Bitcoin.
Coinbase recently announced that its customers in supported jurisdictions can send, receive, buy, and sell the USD Coin stablecoin (USDC) on its website and mobile applications. This marks Coinbase first entry into stablecoins, which have a fundamental difference as compared to other cryptocurrencies. A USDC is pegged to the price of a single US dollar (USD). Coinbase explains that one USDC is represented by one USD on the Ethereum blockchain.
Ripple positions itself as a complement to, rather than a competitor with, Bitcoin - the site has a page dedicated to Ripple for bitcoiners. Ripple is a distributed network which means transactions occur immediately across the network - and as it is peer to peer - the network is resilient to systemic risk. Ripples aren't mined - unlike bitcoin and its peers - but each transaction destroys a small amount of XRP which adds a deflationary measure into the system.