[Ducki]

Does the built-in dictation not use these models or why would I use this app instead of Apple's own dictation?

[pancomplex]

Apple's built in dictation still executes parts of it online and even has a disclosure that it "sends information like your voice input, contacts, and location to Apple."

This project uses the on-device SpeechAnalyzer API directly and makes zero network calls, and since it's open source you can verify that nothing leaves your Mac.