Aren't they just providing access to their service? Different companies provide different billing methods and that's fine!
For example you could pay $20/month for ChatGPT and use it as much or little as you like, or pay $/per API call... But not every company needs to offer both.
For example you could pay $20/month for ChatGPT and use it as much or little as you like, or pay $/per API call... But not every company needs to offer both.