PDAs as alternatives to smart cards?

With the widespread adoption of an industry standard IR link between PDA type devices, networks and PCs might this not present an opportunity for their use as more user-configurable and application agile financial and communiation privacy instruments? I'm especially thinking along the lines of their use for ecash transactions in conjunction with smart card-type merchant terminals sporting an inexpensive IR link to the customer's PDA. If disk protection programs (e.g., DiskCrypt/PGPDisk) were extended to PDAs ight that not enable them for a whole host of personal applications? --Steve