I got MicroSnitch as part of a bundle with LittleSnitch, without really knowing what it was at the time. When I figured it out, I had the same thought as you.

It's definitely not something I'd ever trust completely, not only could it be spying on you, but I also don't really trust my hardware. However, I must say, it's still very nice to have. It at least narrows the possible spying vectors, and it's nice to know immediately what apps are listening; the best example being Android Studio emulator: always listening.