As a first thought keep in mind that OpenAI and Azure OpenAI are slightly different. Azure OpenAI brings and wraps role-based entitlement, more controls and more options (such as private cloud) to the table.
The 100s of Copilots use Azure OpenAI to enrich and empower applications within the Microsoft Stack of offerings. This includes everything from Azure DevOps and developer tools to the Microsoft Business Applications.
In the Microsoft Business Applications Copilot add an entirely new layer of awesome. It cuts through the noise, adds executive summaries, can be configured to find the right knowledge article from YOUR sources of knowledge and can bring filtered and controlled automation into areas that make sense to automate.