Why the Condition and Action mechanism in jass?

What is the benefit of the Condition and Action mechanism in the jass trigger?

It was originally created that way to reflect the design of GUI triggers.

Also, conditions don't start a new thread, so they take less time to run than an action does. People frequently put their actions inside conditions to take advantage of this fact.

However, conditions can't use TriggerSleepAction (the Wait action in GUI).

thanks

And must return a boolean.