macOS already has a dictation feature that does this exact thing, albeit in real time. I use it extensively.
OP’s description in the linked article doesn’t say much more than this, so what am I missing with this particular app?
Apple's own dictation is quite limited, doesn't handle multiple languages very well, and many open source dictation models simply do better.
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Apple's built-in dictation works for casual use, but in my own daily use the typo rate was high enough that I was constantly going back to fix things, which defeated the point (with a hand injury, those corrections cost me). WhisperPad uses Whisper models instead, doesn't cut off after 30-60 seconds like Apple's does, supports 99 languages offline, and pastes into any active field via hotkey. There's a 120-minute monthly free tier so you can see if it fits your use case. If Apple's built-in dictation handles what you need, that's a fair answer.