Interesting! Be curious what this widescreen business is as I don't know much about the SNES but a quick Google suggests some games were suitable.
Guessing they're something similar to an anamorphic signal, with some content sitting in the overscan area? Wouldn't imagine that devs would be keen to write extra code that's gonna sit offscreen the whole time when space/speed is already limited.
Would be thinking that for the time such functionality would only benefit a small number of viewers with widescreen CRTs and CRT projectors (mostly broadcast/cinema grade kit and high-end consumer gear).
I'm intrigued 😃