According to several outlets - most notably Inside Mobile Apps, Microsoft is rumored to be considering dumping its Microsoft Points currency that it uses on Xbox Live Marketplace for real world dollars. Transaction will allegedly be shifted over to real world dollars instead. Naturally transactions would use the currency of the region a given account is in.
This makes some sense if you consider that many of the services and items you can buy on Xbox Live - including new movies, music and Games on Demand don't allow you to use MS Points - you have to spend real money on these things.
For now Microsoft is saying the usual comment because this is a rumor:
"We do not comment on rumors or speculation."