Interlaced at 60 Hz would probably flicker less than non-interlaced at 60-85 Hz, but I've never heard of it being done, probably because it means drawing 120 separate frames a second and require a much faster horizontal scan rate for this. But regardless of the refresh rate, it's easier to draw a complete picture in a single sweep than to line up 2 separate frames with one another because a lot more time passes between frames than between individual adjacent lines in a sweep.