In AX2012 it was easy and simple for a user to hide an unwanted module. That is not possible in D365 FO.
Just because there are common menuitems, users are forced to see those modules.

Turning off configuration keys can be used to achieve that but that's not always the solution. For example, "Released products by category" form is quite useful, but it belongs to Retail configuration key. If that menuitem is given to a user they are forced to see Retail module. If it was possible to hide, users could have hidden Retail module and continue using the same menuitem in Product Information Management module.