Does plugging in my PS4 controller to my PS4 when playing cod reduce input lag or anything or give me better input time?

It doesn't improve input time -- it doesn't make your reactions any faster.

What it can improve is input lag/latency, or the time it takes your inputs to make it to the console. It only improves it by a handful of milliseconds, so only top-tier gamers usually notice the difference. There's also less chance of interference and you don't have to worry about charging batteries.

If anything, it will reduce lag. Wireless is not as good as people want to believe. I have a friend who plays at the top-tier. He's hardwired for everything. I asked him why and he said because the pros do it.

Does it matter?