To a layman, they're all useless, and in a dangerous way: they transport a sense of understanding a person/character/psyche that they don't support. A professi

To a layman, they're all useless, and in a dangerous way: they transport a sense of understanding a person/character/psyche that they don't support. A professional can gain _some_ information from all of them. Just that the Big 5 have much more literature behind them than MBTI, so there's more reference data for any given constellation. That's a reinforcement loop. Methodical differences and reliability and all that fluff can be used to argue in more detail in favor of one versus the other, but by now, it comes down to what folks are more familiar with. In the end, these are just a few out of many, many tools of the field. If you see somebody build their career on "(MBTI|Big 5|...) analysis" and nothing else, they're not a professional but a quack.