We're certainly in favor of competition as well as a truly free market in currencies, so we do accept all kinds of things in trade for our products and services. Most alternatives are physical, such as traditional bullion, so they would need to be delivered to us somehow. This does complicate things some, but we have done this before so we have handled it.
We often get asked if we can convert some regular bullion into our cards. While we are happy to make such a trade, it should be noted that we aren't actually going to melt down your silver to make our cards. Instead we would likely sell the bullion for dollars, then turn around and order some new bullion in the form we need.
Before you send us any alternative currencies intending to trade them, please contact us so we can work out the details. We're willing to make some deals, but we do carefully calculate them to make sure we aren't losing money on the deal.