The benefits of the browser API are that it is free, you have to pay for any of those APIs to use them directly, and you don't have to handle the streaming connection to the API, the browser does it for you.
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Behind this browser API is the Google Cloud Speech API and there are plenty of other speech to text APIs available, like Amazon Transcribe, IBM Watson Speech to Text and Azure Speech-to-Text that you can use in any application to achieve this. For example, here's a blog post on how to use the Google Cloud Speech API to live translate a Twilio phone call.
The benefits of the browser API are that it is free, you have to pay for any of those APIs to use them directly, and you don't have to handle the streaming connection to the API, the browser does it for you.