The amount of body-kits and JDM is exponentially higher at a time attack. And apparently based on this video the driving skill is highly variable, which adds considerable excitement. You are way more likely to see some lawn mowing at a time attack.
In short time attack seems to be for highly modified cars, and trials are more for classed race cars, although this is just a generalization.
Id love to go watch some amateur time attack events that’s for sure. I love me some carnage.