Ediff: compare two (long) buffers Word-by-word

[ST]

Hello,

I use Emacs 26.1 and try to compare two (long) buffers (opened side by
side) by clicking Tools -> Compare (Ediff) -> Windows Word-by-word...
Then I choose both Windows (A and B) by clicking on each opened buffer.
However it looks like Emacs compares only the visible parts of the two
buffers, not the whole buffers. Why?

I saw there is a command `ediff-windows-wordwise`... How is "Window"
defined? - as "currently visible part of a buffer"? If yes, is there
something like `ediff-buffers-wordwise`?

I have `git` in `exec-path`, so maybe I can make ediff to display the
output of `git diff --word-diff file1 file2` in ediff style?

https://emacs.stackexchange.com/questions/46161/ediff-compare-two-long-buffers-word-by-word

Thank you!