I don't want to defend XRP here, but....

What's the true purpose of cryptocurrency? there's no such standard, as long as it's a digital/virtual currency that using cryptography to make it secure, it will be said as a cryptocurrency.

Any cryptocurrency don't need to be decentralized like Bitcoin, it's no need to have a high volatility like Bitcoin, it don't need to be transparent like Bitcoin. It don't need to be same like any existing currency, if it's same, what's the reason to create it?