> It's a tool for some jobs; definitely not all.

I'd completely agree. I would not use C for doing any web platform work (writing a REST service as you say). I may write a webserver in C if I had tight memory constraints.

Where I see C still being very useful: embedded applications, drivers, and latency sensitive code.

When you are trying to push the most I/O possible through a network interface or disk interface, C allows extremely tight controls on memory and CPU usage. Especially if you are coding to a specific CPU for an embedded product, you can really tweak the app to perform as required (though, this may require some assembly to do what you need).