I am curious about the IIf.

As I understand, IIf is an if function that checks for both true & false conditions. This seems a disadvantage to me because 1) evaluating both conditions causes the code to take that little bit longer to run and 2) what if one of the conditions results in an error? (whereas if you only checked one condition, this may not have happened).

Is there any advantage to using IIf? If so, what is it?