I don't think those reasons create the legal differences that you are presenting. Consider the Liberty Dollar [1], it was a currency that is backed by physical

I don't think those reasons create the legal differences that you are presenting. Consider the Liberty Dollar [1], it was a currency that is backed by physical entity (precious metals) and it is directly backed by a company. With the exception of a federal law that specifically mentions using metals as currency, Bitcoin and Liberty dollars are direct legal analogues. I think the real difference is the usage intent. Microsoft points are simply gift cards that can only be used for the companies own products, Microsoft is not trying to have microsoft points replace dollars for exchanges between two arbitrary parties unlike bitcoins and liberty dollars. [1] http://en.wikipedia.org/wiki/Liberty_dollar http://en.wikipedia.org/wiki/Liberty_dollar