In FileMaker, there are some commands which can only be accessed via various tool palettes (Inspector and so on). This can make them harder to find and access. When every command is available starting from the menu bar, it makes it much easier for new users to find commands. It also empowers experienced users who can assign their own keyboard shortcuts (using OS-level commands or other utilities), even when one is not initially assigned. It greatly improves the software's scriptability, as well. It is better for accessibility than palettes that a user has to scrub around on to find a command. On the Mac, the Help menubar item even allows you to _search_ existing menu items, so that improves discoverability further.
Please consider creating a menu item for every available command, particularly in Layout Mode. Don't bury commands in the inspector (or other) palettes.