I have no clue why physical sliding keyboards basically disappeared from "smart phones"... they are not only good for the blinds (I guess they probably make pretty much the same amount of money whether they include it or not)
And if we're talking about typing on a physical device, a fair number of visually impaired folks I know have bluetooth braille displays (e.g. note taking w/iPads in class), or you can sub a regular keyboard to that instead if wanted (if you don't want the display either).
From my sighted but alternative perspective on why physical keyboards built into phones is not the best idea either, I enjoy being able to type in English and Korean, then swap over to Chinese handwriting when needed. I don't have the same thumb typing muscle memory for other languages/layouts than I do for qwerty, so it's great to see what I'm typing occasionally.
As for alternate keyboards, Fleksy has been popular among blind iOS users.