macOS has dictation built in and it's free. So why pay for anything? Because what comes out is very different. Here's the honest comparison.
Mac dictation would type the ramble on the left, ums included, with no punctuation unless you said it. Speaky Box types the message on the right.
It's free, it's already installed, and for a sentence or two in Notes it's fine. On recent Macs it runs on the device for English, so nothing leaves your machine. If you dictate rarely, use it and don't pay anyone.
It gives you a literal transcript. Say "um" and you get "um". Change your mind mid-sentence and both versions appear. Punctuation is your job: you say "comma" and "full stop" or you get a wall of words. Names and technical terms are guessed from a small on-device model, and it produces the same output in a prompt box as in a text message.
You hold a key, talk normally, let go. The text arrives finished: punctuated, ums and restarts removed, grammar fixed, your names spelt right because you added them once. Hold the Smart key instead and it writes for the app in front: an email in Mail, a message in Slack, a structured prompt in Claude.
Both capture speech at talking speed. The difference is what you do afterwards. With Mac dictation you re-read and fix. With Speaky Box you send. Over a day of messages and emails that's most of the saving.
Mac dictation keeps English on the device. Speaky Box sends audio to a speech service, gets text back and deletes the audio; your history is stored on your Mac and can be turned off. If nothing may ever leave your machine, Mac dictation or a local tool like Superwhisper is the right call.
you dictate occasionally and don't mind cleaning up afterwards. It's free and it's already there.
you write a lot, you talk to AI tools, or you're tired of saying "comma". The text arrives finished, and in Claude it arrives as a prompt.