“What would it mean for your business if you could target potential clients who are actively discussing their need for your services in their day-to-day conversations? No, it's not a Black Mirror episode—it's Voice Data, and CMG has the capabilities to use it to your business advantage.”
This is why I generally ensure my phone is configured ahead of time to block ads in most cases. I don’t need this garbage on my device.
As for how they could listen? It’s pretty easy.
By waiting until the phone is completely still and potentially on a charger, it can collect a lot of data. Phones typically live on the nightstand by your bed at night; and could be listening intently when charging.
Similarly it could start listening when it hears extended conversations; simply by listening to the microphone for human speech every x minutes for y minutes. Then it can record snippets; encode them quickly and upload them for processing. This would be thermally undetectable.
Finally it could simply start listening in certain situations; like when it detects other devices (via BT). Then it could simply capture as many small snippets of your conversation as it could.