I think the main technically interesting thing is that it adds custom functionality to cheap, mass-produced hardware. If you wanted to build a clock completely from scratch, it would be a significant amount of work to design something that works as well as a $10 wall clock from Walmart. If you just figure out the right way to interface with that hardware, you can do interesting stuff a lot more easily.

It's a little bit reminiscent of how people figured out that you could use cheap USB TV tuners as software-defined radios, although obviously this project is a lot simpler than that.