My first thought would be that a menu item might get lost, if you have another app open, then decide you want to go to your "storage" menu item. (Some apps might not leave a space for your custom menu item, and just ignore it, unless you can figure out how to make it system-wide, so it is accessible at all times). Apple developers usually have limits on how they can bypass the standard Apple menu layout, and "custom" menu items would probably be ignored entirely by some apps (and your custom menu item might not even be visible when another app is active)
Sounds to me like it would be easier to have an icon in the dock for your saved text file, where it would always be one-click away.
I use much-the-same thing for rarely used internet logins.
And, you might want to try out your Automator app, as that can make simple things like you want, easy to use.
There's other apps on your Mac that do similar tasks: Notes, or Stickies, or Reminders, etc.