On the flip side was getting busy signals because of there not being enough capacity somewhere between you and the person you were calling, and also cross-talk issues, where you could hear other peoples' phone conversations on your line.
If you run ytalk on a modern machine, it doesn't flicker, but you can still get every keystroke, because that's the protocol.
w.r.t broadcast video, the eye/mind can still pick out an image from a static-filled snowy image, but digital artifacts from low/poor signal result in freeze-frames and garbled mess.
Summary: Digital. When it's good, it's very good. But when it's bad, it's awful.