Very location dependent. But when you learn to write the characters you understand the variants differently. They look like random strokes to an untrained eye. But they’re not. I’m not sure if that makes sense.
Take a lowercase a in English for example. This font writes it differently than a child. Or in cursive. Or probably than you would write it. But you recognize all of them and don’t really think about it.
Traditional kinds are usually recognizable, but I'd be unsure or straight up wrong about most Simplified versions. Overall proportions and small details often feel "wrong" for both as well due to cultures converging at different points.
Do people usually recognize all variants as valid and legible? Or does any particular set of letters/symbols prevail in practice?