In reply to Quite Simple.

While the people who write in multiple languages frequently will find this a useful button, the number of people (as a percentage of users) who that applies to is going to be pretty low. Those uses could be accommodated by having an alternative multilingual keyboard layout (maybe meaning only the return of this button).

Seems like there are many other characters that would be used much more frequently but a massive % of all users for which that button space could be better leveraged.