[*] limited bandwidth (8 kHz), providing a valuable opportunity to enhance and specialize models for telephony applications, ensuring better performance and user experience even with low-fidelity audio inputs.
I mean, nothing prevents them from running their existing data through a "noisy POTS" filter in A/B tests to see how that impacts customer satisfaction.
But being able to blame the user's phone line probably goes a long way to avoiding unhappiness due to testing :)