By identifying the purpose of an ad, you are able to see what it is actually about. If you didn't know the reason behind the purpose, you might be confused as to why is this ad even an ad overall. Whenever you find out the suitable audience the ad is directed to, you are able to see if it's suitable for you. For example, if there was an ad featuring a men spray a female would most likely not buy it but a man would. This is the same for the other gender. Of course if some females like men spray, they would buy it. However, you can clearly see that, that ad is forwarded towards men.
