If it's a scrum advantage, you ask yourself what they would expect to get from having the scrum. Basically possession and the opportunity to play the ball without undue pressure. If they choose to kick, they have used their advantage regardless of whether or not the kick was a good one.
If it's a penalty advantage, the expectation is different. Even a good kick to touch might not be considered advantage since it would give away the throw.
If it's a penalty advantage, the expectation is different. Even a good kick to touch might not be considered advantage since it would give away the throw.