I agree with this, but something to note here is that usually people have ads across multiple networks. We used to manage ads on Google, Facebook, etc. These

I agree with this, but something to note here is that usually people have ads across multiple networks. We used to manage ads on Google, Facebook, etc. These would be the same or extremely similar ad campaigns running simultaneously. The reason for this is that you get different clarity to groups that you advertise to, different performance metrics, different costs, different exposure numbers, and generally get to target to more people doing this. Not everyone uses Facebook, not everyone is Googling something relevant to your ad campaign at that time.