TL;DR: XRP have increased [edit]shorter[/edit] transaction times and use less ressources. Why still use Bitcoin when we have XRP?

I'm not trying to troll, it's a serious question.

I have been very critical about XRP before, but my main point of criticism has always been Opencoin's position as the "XRP central bank", as they still hold about 99% of all XRP in their possession. I tried to get more information about XRP, and someone directed me to this link: https://ripple.com/wiki/Consensus. If I understand correctly, XRP solve at least two major problems of Bitcoin: Transaction time is much faster, and they require no mining, which means that less energy and hardware is used to secure transactions with the Consensus system. I assume there is also no need to store the blockchain on the hard drives of thousands of users. Sounds pretty good to me?

So for the sake of argument, let's assume that Opencoin is now and will always be an altruistic and trustworthy entity that will never under any circumstances abuse their position, and that they will indeed distribute the XRP in a manner that would be deemed "fair" by the majority of users, and that they will not secretly hold on to the majority of the supply.

In this case, wouldn't it be preferable to abandon BTC and start using XRP instead? What are the disadvantages of the consensus system over the proof-of-work system? Are XRP (or at least a similar system) the future of cryptocurrencies? Will they make Bitcoins become obsolete?