Why do I need vim in binary mode for 'noeol' to work?

Question

This question is a follow up to the Work Around I use for \"saving files in vim without having the newline at end of file forcibly added\" annoyance.

Basically I can

Answer 1

have a simple preference in .vimrc to NOT add newlines at every single file i edit

You can use my PreserveNoEOL plugin for that. With this simple setting, you're done; alternatively, you can also influence this per buffer:

:let g:PreserveNoEOL = 1