Explanation
These two metrics are useful for identifying knowledge article effectiveness, as they indicate the gaps and weaknesses in the knowledge base. Knowledge search query with no results shows how often customers and agents search for something that is not covered by any article, which suggests a need for creating new content.
Knowledge articles with the lowest rating shows how satisfied customers and agents are with the quality and relevance of the existing articles, which suggests a need for improving or updating the content. Verified References: Report on Salesforce Knowledge Articles and Knowledge Base Dashboards & Reports

Explanation
Embedded Chat Service is a feature that can meet the requirement of allowing customers to interact real time with support agents from their computers and mobile devices. Embedded Chat Service allows administrators to embed a chat widget on any web page or mobile app that customers can use to start a live chat session with an agent. Embedded Chat Service also supports features such as pre-chat forms, chat transcripts, file transfer, and chat transfer. Verified References: :
https://help.salesforce.com/s/articleView?id=sf.snapins_chat_overview.htm&type=5 :
https://help.salesforce.com/s/articleView?id=sf.snapins_chat_setup.htm&type=5