It's not just a workspace layout, it does have those but they're separate from the modes. Different modes (object mode, edit mode, sculpt mode, texture paint mode, weight paint mode, etc.) all have different hotkeys and in many cases have functionality that aren't available at all in the other modes. There are some conventions shared across modes, like G/R/S hotkeys for move/rotate/scale, or X to delete things. But the majority of blender's operations are mode specific.
If you're in one of the painting modes, F is the hotkey to change brush size. But you can't add faces in the painting modes.
If you're in edit mode, F will create a face from the selected vertices or edges. The concept of a brush doesn't exist here.
If you're in object mode, F doesn't do anything.
For another, I is "Inset Face" in edit mode, but "Insert Keyframe Menu" in object mode. This one is a bit different, because the keyframe menu is actually available in any mode and it just doesn't have a hotkey unless you're in object mode. But like the other mesh editing tools, Inset Face only exists while you're in edit mode.
If you're in one of the painting modes, F is the hotkey to change brush size. But you can't add faces in the painting modes.
If you're in edit mode, F will create a face from the selected vertices or edges. The concept of a brush doesn't exist here.
If you're in object mode, F doesn't do anything.
For another, I is "Inset Face" in edit mode, but "Insert Keyframe Menu" in object mode. This one is a bit different, because the keyframe menu is actually available in any mode and it just doesn't have a hotkey unless you're in object mode. But like the other mesh editing tools, Inset Face only exists while you're in edit mode.
Screenshots for reference:
Modes https://i.imgur.com/nmKeP2f.png
Workspace layouts https://i.imgur.com/7g61twc.png