It's quite tightly integrated, so even for a fee business, you'd likely need sales and inventory to create a fee item to invoice.
The security setting in 'access setup' normally just disables the menu links. There is an option 'hide_inaccessible_menu_items' when set will stop the disabled menu items from being displayed. You may need to add $hide_inaccessible_menu_items = 1 to config.php. It used to be there, but I don't see it in the current release of config.php.
I think kvvaradha was trying to say that if you leave access to components you'll actually find it quite useful. But using the role access permissions and menu item hiding, you can probably get the best of both worlds.