Shoplifters? Studies Say Keep an Eye on Workers

So, we now have the credit infrastructure widely disbursed. In fact, it is so in place that we now give out credit cards (well debits... but functionally the same thing) instead of checks for gifts, rebates, refunds etc.

The presence of different types of accounts: credit, checking, savings, etc. backing these cards further indicates the expensive bits of infrastructure are wired togeher.

A while ago people developed cryptographically secure e-cash systems.

Why oh why can't we just combine them together now? Sophisticated fraud protection is already very good, and can still apply, meaning we don't need perfect crypto. Good e-cash systems for in-store credit would allow the tracking of who frauded someone. The general concept would allow for secure online transactions. Fraud would be easier to track down. Conversions to real cash, as well as natural pooling places such as banks would allow for mixing the units, such that the privacy folks don't have much to worry about, not much more than currently anyway.

What am I missing for such to occur?