Any use cases of `iso-transl-language-list'?

[Tor Kringeland]

I was looking at `iso-transl.el' and came over
`iso-transl-language-alist'.  By calling `iso-transl-set-language' and
selecting one of the languages you can input certain characters using
one less key-stroke with `C-x 8'.  For example, by enabling Portuguese

  C-x 8 c

produces "ç", which can also be done with `C-x 8 , c'.  Except for
Esperanto and German, I do not see why this feature is necessary,
though.  In the first place, it would be much easier to use an input
method instead if you want to write in one of those language.  Moreover,
support for French, Portuguese and Spanish are incomplete, and could not
be completed using the same pattern.  /E.g./ in Portuguese you have both
"é" and "ê" so there's no good answer for what `C-x 8 e' should do if
you had enabled Portuguese; and one key-storke more (`C-x 8 ' e' or `C-x 8 ^ e')
would produce either character without having to choose
Portuguese as the input method.

This feature seems to have been implemented around 1995, and I would
guess a lot has changed since then with input methods in Emacs.  It does
no harm, of course, but is there really a use case for this anymore?  Is
it something that could be deprecated (at least for Portuguese, Spanish
and French, for which I cannot see any real use case with the current
implementation) in favor of input methods or using the regular `C-x 8'
map, which for each character only requires one key-stroke more?