The primary purpose of mining is to allow Bitcoin nodes to reach consensus about the blockchain. It is intentionally resource intensive. It takes 8-10 minutes. And it is subject to a 51% attack.
I believe that the Ripple protocol's method for reaching consensus is superior to Bitcoin's. It is orders of magnitude faster (2-5 seconds vs. 8-10 minutes). It is not subject to the 51% attack. It is not computationally expensive or resource intensive. It seems like a better design to me.
Ripple protocol =! XRP. If you don't like XRP, then don't buy it. Easy solution. Ripple is still valuable as a protocol, since it's currency agnostic.
@Goldenkey - While we're making demands of each other, please take your logic-free and malinformed vitriol off HN.