Ok so on paper Peercoin might be have some better features, but why should I use it instead of Bitcoin?
You probably wouldn't use it but the crypto-economy in general would use it to make small numbers of extremely large monetary transfers.
That's what it was designed for. To be a monetary backbone - and before you say "why can't I just use Bitcoin for that", it gets technical and has some economics criteria thrown in. Suffice to say, it's one of the coins that had a lot of thought put into the role it would adopt in the crypto-economy.
Have a look at this video:
http://www.youtube.com/watch?v=ynwz8H66chYThat is now almost a year old and Peercoin is STILL in the top 4 marketcap coins. That is amazing and is not due to being "kept up there by traders".. If DRK can do that in a year's time it will be in with a high chance of being here for good.
It might have some value and some use cases where it beats other cryptos, but if we are talking about driving the price, the only this to do that is mass adoption. DRK has a feature that can drive mass adoption (when I say mass adoption, I still see it as being behind BTC for quite a while, if not forever).