Can someone tell me please if is a good idea to use TFS as ticket manager for end users and in the same time as backlog for team developpers?
Not totally sure which kind of ticket manage system you are referring. For tickets, if you mean the ones raised by the end users of an organization whenever they encounter an event that interrupts their workflow.
Then seems you are looking for a helpdesk ticketing system, acts as a documentation of a particular problem, its current status, and other associated information. These tickets are routed to a ticketing software where they are categorized, prioritized, and assigned to different agents according to the organizational norms.
The agents then analyze these tickets and suggest appropriate fixes or workarounds and resolve the issue. As a central repository of all these tickets, an IT Ticketing Software helps in providing the context of the issue history and its resolution.
Then to be honest, this is not what TFS should do. You may have to look for some other system to handle this.
TFS provides integrated tools to support collaborative software development, including Git repositories, continuous integration and continuous deployment (CI/CD), and interactive Kanban boards.
You could also collect bug/feature request and related info from end users, then track them in TFS.
But it's not suggest to let them directly access your TFS system and fire work items by themselves. Cause you need to assign them license and corresponding permission.
TFS fully supports bug tracking and traceability though the code that was changes.
The out of the box bug work item is specifically designed to work with the test tools and the planning tools. Besides, you could also use them and add a few customization to meet your requirements.