Almost all Sharia banking is just religo-legal fiction. It's just a way of organizing the deal so the interest is called something else.

Basically, there are two types of people who are attracted to the idea. The first are religious fundamentalists, who are only interested in following the written rules not the spirit behind them. The second are those who actually want to get rid of usury.

The second are inevitably disappointed when they realize that nothing has changed except the terminology and that is why it won't become popular in the US. There are not enough of the first to have a big impact.

Jay