Gonna make an assumption that the question is about the difference between M365 Copilot vs Security Copilot and give my 2c,

M365 Copilot is for end users, administrators, and non-security chaps where the use case is for productivity, operations, etc. Security Copilot is focused around the 'security' aspect. Even in embedded experiences,

• Security Copilot in Entra ID is mainly for managing CA policies
• Security Copilot in Intune is mainly for managing device security policies and finding gaps
• .. so on

From a pricing model - M365 Copilot follows per user license, and Security Copilot uses compute cost (SCU) model. For example, if you spin a virtual machine in Azure - it doesn't matter how many people are gonna be using or accessing it. It will be charged based on how much compute it takes to run the machine on cloud. Security Copilot follows a similar approach instead of tying it down to a user. Hope that makes sense! :)