Coinbase requires you to link a bank account, or credit or debit card to your Coinbase account to purchase cryptocurrencies. Using a bank account allows for higher limits ($100/transaction, $2,500/week), but it also takes longer to verify transactions, so you will not see money in your Coinbase wallet for two to four days (depending on your bank). And when selling Bitcoin, once the sale is confirmed, it takes two to four days for the proceeds of that sale to show up in your bank account. With a credit or debit card, limits are lower ($200/week), but you can purchase digital currencies by simply transferring funds from that bank account to the site. For these transactions, Bitcoin shows up in your Coinbase wallet instantaneously. You can also sell Bitcoin to your PayPal account, effectively cashing out, as your Bitcoin will be exchanged for local currency. This transaction, too, is instantaneous.
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.
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.