Emotions is a must for humans. The only thing i can think of an emotionless human, is not human.

Tools that we called today, were made by humans. Tools are emotionless but human decides on what type of emotions the tools will be depending on their liking.

Take example of knife. Knife is emotionless, but it can be used to chop stuff or kill people. There are no hesitating in knife when it comes to action. But humans are different.

If i use a knife to kill people, yes, percentage of succeed is always 100%

If i use human to kill people, no, percentage of succeed is varied depends on their emotions.

Tools (emotionless) are not = to Humans .

There is no such thing as advantages and disadvantages of having emotions. Saying that is like saying there are advantage of having a brain, and not having one. It is part of what makes human. It varies from how one's manipulate it. Emotion is a critical factor in every humans and this factor is one of the factor that varied us from one another.