Are the box weapons op?

I'm curious about this since it seems like each game i get bodied by people using weapons from the loot boxes you can purchase, so does this mean that these people are just stupid good at the game? Really good with these weapons? or are exploiting really op items? If that last one is true does that mean that bo3 is pay/gamble to win? This is not out of hate I love the game but I am curious