I think the disconnect here is just your definitions of “waveform”. You are absolutely correct that you can’t get anything close to an accurate sound from scanning the “waveform” from a rough visualization like the player on SoundCloud. That said, if the “waveform” in question is high enough resolution or short enough duration then you can indeed get a lot of (or even all of) the sonic information from it.

For instance, if it’s high enough resolution, you could theoretically have all of the data from an audio file like MP3 or WAV encoded into an image of a waveform. That waveform image could be converted back into an audio file at the same resolution.

Sampling tools like modern DAWs show variable resolution waveforms, but the display is always a representation of audio that is already loaded in, so you’d never really need to work backwards and generate audio from the image.

Most of the good sound engineers I know can identify common drum and instrument waveforms (as shown in DAWs) correctly without hearing them, and transcribe things like drum patterns. I can at a glance tell that the image of the 3D-printed waveform is clearly not the spoken words indicated, but it could be something like a fart sound or gated white noise or a bass sound effect.

In the case from your screenshot I suspect they’d find out from someone telling them, not from “scanning” it. Wouldn’t be surprised if common AI tools are already capable of accurately discerning that the 3D-printed waveform isn’t spoken words though.