Let me paint you a scenario.
It's night. You're in bed, fresh off a shower, and ready to sleep. You feel yourself dozing off. You're jolted awake at the sound of footsteps heading up the stairs. Something is clearly wrong because the wife and kids are away for the weekend. You're afraid, but fortunately you're in reach of a PS4 game cover, inside of which is a blu-ray disc. No sooner does the thief invading your house open your bedroom door, you throw that disc like a well trained ninja and it hits a critical point in the home invader's neck.
He falls to the ground. You're safe, and sound. You can call the police, and later inform your wife of your heroics. It's a nice story.
Now imagine you had no game disc. The home invader enters your room, and all you can do is throw air at him. Because that's what you have without a game disc. Your "attack" doesn't work. That thief then beats the shit out of you, strangles you with your own penis since you're a GAFfer and it's big enough, and then throws you out of the bedroom window. While he scours the house for your valuables, you lay on your lawn like the little lamb who thought he knew better before the wolf made him fucking dead.
So how about you start appreciating the versatility of the physical game disc?