Amazon library?

In another "re-invent the wheel for fun and profit" move, Amazon has launched a new initiative lending books to Kindle users.  Apparently, Amazon Prime customers can "borrow" one book per month from Amazon's vast sources.  There are a couple of catches with this plan though:

1. The Kindle owner must be an Amazon Prime member.
2. The Kindle owner must be just that - an owner of a physical Kindle device.  The loan service will not work with the Kindle app.

Is this a good deal?  I suppose it depends.  If you already have a Kindle and you want to shell out the annual $79 for Amazon Prime membership too, then yes.  Amazon Prime has all sorts of other advantages with shipping, etc.  However, it won't be long before public libraries everywhere have large collections of ebooks for patrons to borrow on practically any device they want, including Kindle and Kindle apps devices for free and at a higher rate than one per month.