I’m not
@Micah Sweet but I can give a solid example of the point.
Consider a character who is an alcoholic. This is probably a strong driver of behaviour and (assuming being in recovery) it might well make sense for the character to avoid situations where they are tempted to succumb to their addiction.
In a game like GURPS, while you get some benefit from taking Alcoholism as a disadvantage during character creation there is no upside during play - it’s all downside from there on. So, as a player, it makes sense for you to also avoid situations where your disadvantage could come up.
Contrast that with a game like Fate where being an alcoholic would probably be an Aspect. In that system there is little / no upfront benefit from taking this aspect; the benefit comes from having your aspect impact you during play. So as a player, there is incentive for you to engage with scenes where your addiction will negatively impact you.
Hence, with a system like GURPS the player is incentivised to act
consistent to the behaviours of a person who might have such a disadvantage. While in Fate the player is incentivised to act
counter to the behaviours of a person who might have such a disadvantage, notionally in the pursuit of a more interesting story.