I don't think my glasses can correct my vision well enough to be able to read 80-char-wide text on a smartphone in portrait mode. I can't say for sure because I don't own a smartphone--partly because I worry about being able to read web pages on it without regularly resorting to the aforementioned tedious horizontal scrolling.
I always wear my glassses when I'm using my iPad, which is in landscape mode almost all the time (the exceptions being the rare apps like Uber's that won't do landscape mode).