I just tested on my Mac running 10.13.3 beta and enabling the "always show ~Library" changes the effect of the various modifier keys when used with the "Go" menu.
- ~/Library is ALWAYS on the go menu regardless of modifier keys
- SHIFT — switches to wide menu display and changes "Enclosing folder" to "Select Startup disk on desktop"
- OPTION — changes the "Enclosing folder shortcut" from ⌘↑ to ⌥⌘↑ (I have no idea why)
- CONTROL — Same as Shift
- COMMAND - no effect
I'm seeing (in 10.12.6) the same thing you just reported, except control changes "Enclosing Folder" to "Enclosing Folder in New Window".