It's a good option for embedded, especially low resource embedded, applications. Provides a nicer set of abstractions than assembler and let's you create basically a tuned DSL for your problem. That said, development doesn't scale particularly well, multi-member dev teams are hard, and maintenance of someone else's code can be, shall we say, challenging.

I always wondered how Sun and Apple addressed this, as they used forth in the form of OpenBootPROM as a boot environment on various platforms. Very, very nice.