Straight to the point would be good if you could see prices in other currencies. As this is an international forum/marketplace not just for US. It would be a good feature and slightly more welcoming for 50% + of DP's users. A lot easier than using a currency converter.
I'm not sure I understand your point. If we had all these different currency prices here on the market forums it would lead to confusion. Then those of us who are used to thinking in U.S.$ would have to use a currency converter. So what would be the advantage here?
I'm not from the USA, but have no problem working in USD. In fact, it makes life simpler as most things relating to this sector are usually in USD anyway. Plus, it's not rocket science to keep track of your own currency vs USD, so you can always do a quick estimate without loading up a currency site.