This is not for you, it's for an IT department with a nontrivial number of desktops. You pay again because centralizing users on a single machine that you can update/troubleshoot/fix/install software on once is often more cost-efficient than trying to manage 1000 autonomous Windows desktops.
I know it is not designed for people like me, else I'd be asking where the Linux options are ;)
I don't work with a company that has a large IT deployment anymore but when I did their processes was not that different. They had a single image that was on every single PC and contained "standard" software. If there was any kind of problem with the machine, they'd just reimage it remotely (PXE) and if it still had problems they'd just send the machine back to Dell and get a replacement.
Although management/maintenance was not really my point. Rather, if you already have functional working machines with Windows / OS X (or have to purchase them) then Amazon WorkSpaces seems expensive. If it was accessible via some cheap thin client that did not require a separate client OS license (+ the hardware that comes with machines ables to run Windows / OS X) then it would seem more appropriate.
This is common, but Virtual Desktop Infrastructure is increasingly common currently. The only novel thing about Amazon's program is that the server is in EC2 instead of the corporate server closet.
As I understand it, some of the motivators are:
1) The image is immutable (by normal users). Each startup is clean, so the potential to screw up your install is very low. Only user folders (redirected to network storage via GPO) persist.
3) Unlike an RDP setup, each user has their own OS instance so you don't have concurrency issues.
4) Windows Server and User/Device CALs are indeed very expensive. However, license costs for the clients are not even slightly relevant because mainstream desktop/laptop hardware comes with mandatory OEM licensing anyway and large businesses are not typically building their own PCs.
