This is tough because automatically updating the images involves reverse-engineering ancient icon formats (literally dating back to Windows 3.1)
There are libs for this, as well as command line tools, that could be incorporated into your build workflow. Electron's rcedit comes to mind. With your new pricing scheme shortcuts like that don't look too good, honestly.
This does not meaningfully improve the security of your game, if that's what you want. I'm not sure what anyone can do with your game even if they can open dev tools anyway, the code is all minified and already has reverse-engineering protections. If you just want to turn off the option you can already apply the command-line argument from within C3.
An argument could be made that you want your game as clean and professional looking as possible. If a youtube reviewer like John Bain or Indiegamerchick or someone of that caliber comes across "leftover debug tools in a release build" by accident, they will rip you a new butthole.
NW.js games don't actually need an installer, so this seems like a benefit? If you really want to make an installer that just copies files to an install directory, there's plenty of free software projects out there that can handle it.
While I basically agree the competition offers it, for less $$$. So not having it is a wound left untended.