Ripple recently replaced etherereum in the second place and also backed by the banks. RIPPLE is also centralized and partnered with big company like moneygram. I might say that those factors are the caused of its hype plus a convincing news that manipulate an investors mind telling them that RIPPLE is the next big thing and the next bitcoin (which is really impossible). Still, when playing in the market, you also have to play with the hype, the number of its supporters and how its platform will benefit all of the investors.
Sorry but you're mistaken. If it is true that XRP is currently centralised, you can't ignore the fact that they are decentralising it since 2012, and about to hit their next phase. It's the same about Cardano, it's easier on a technical standpoint to start as a centralised crypto-currency even when your long-term goal has always been to be a decentralised one.
https://ripple.com/dev-blog/decentralization-strategy-update/