Yeah, it's a binary blob, but it's small enough to be easily auditable. Anyone with some knowledge of x86 assembly can read the annotated version [1] and verify that it does what it claims (which is to convert ASCII hex with comments into binary).
You're right, it also requires a Linux kernel, and of course, you also have to trust the hardware you're running it on. Still, it reduces the amount of stuff we have to take for granted as trusted, which I think is a good thing. (I'm not involved in the project, just an admirer).
