Whoa......wait a minute. Wait just a dog gone minute.
Check out my avatar. I have a scoped Ruger Mark II pistol that might be my most favorite gun to shoot. It is NOT a self defense or home defense gun. It is my plinking/target gun and I can't tell you the countless hours that gun has brought me a whole lot of fun. Ask Stalkingbear......I can shoot the snot out of a clay pigeon set on the ground at 50 yards with that thing.
On the other hand, I would never scope a self defense or home defense gun. That makes no sense at all for more than one reason.
How does your friend use his P220? Okay, I just looked up the specs on this gun and saw it was chambered in .45 ACP. Yep, I agree. I can't figure out why someone would scope a gun like that unless, as Smooth says, he shoots it competitively.