I use it few times a year to fix websites sending ISO-8859-2 (or Windows-1250) and the guess mode worked. As an user affected by this change, it is an improvement (less need to click around trying 5 different encodings)
I am definitely not against the addition of the guesser. It was added a bit before the encoding menu was removed, though, so there was a time when they were both there. I mainly wanted to draw attention to the removal of the menu.