[verdverm]

The main issue is that people think in terms of USD. The prices on the page would still be USD. Every currency is talked about in terms of it's price in USD.

Why have the extra coins and conversions, as a consumer? Even if the companies want to use them like DerpCoin (see Hermitcraft), they will still have to take USD. So will they really ever gain sufficient usage to warrant the company time / people investment into supporting them?

I also suspect most people are involved in many more economic microsystems, which sounds like a business I transact with by another name.