Amazon Q limited to intranet (in-house users) and not for website visitors?

Based on the available information, there seems to be a misunderstanding in your question. Amazon Q and AWS Chatbot are separate services with different purposes.

AWS Chatbot is primarily designed for internal team use within chat platforms like Slack, Microsoft Teams, and Amazon Chime. It's not intended for public-facing websites or for use by external visitors. AWS Chatbot allows teams to manage AWS resources, receive notifications, and perform DevOps tasks within their chat environments.

On the other hand, Amazon Q is an AI-powered assistant that can be integrated into AWS Chatbot to provide expert guidance on AWS-related questions. When added to a configured AWS Chatbot channel, team members can ask Amazon Q questions about AWS services, troubleshooting, and best practices.

The setup process you're referring to, which involves adding policies and configuring guardrails, is specifically for enabling Amazon Q within AWS Chatbot for internal team use. This is not related to creating a public-facing chatbot for website visitors.

If you're looking to create a chatbot for your website that can be accessed by all visitors, you would need to explore other AWS services or third-party solutions designed for that purpose. The Amazon Q integration with AWS Chatbot is specifically tailored for AWS administrators and developers to get AWS-related assistance within their team communication channels, not for public website interactions.
Sources
AWS Chatbot Features - Amazon Web Services
Chatting with Amazon Q Developer in AWS Chatbot - Amazon Q Developer

Amazon Q Apps are a feature within Amazon Q Business, which is intended for use within an organization by authenticated users.