Nothing wrong with doing that (^^^). The issue is if he takes off the bumper skin and finds damage underneath....you've already agreed to the cost to repair, accepted the check, and closed your claim.

And what if something goes wrong in a year, maybe there was contamination on a part and you get a paint blister? In your case maybe you are cool with it, but some people may find themselves SOL.

Finally, I take pictures of damage, insurance claims, work orders from the body shop, and stuff them in a folder if I ever sell the car.

I can tell you if you have to tell a potential buyer "A buddy did it" you will suffer more devaluation than having a work order from a recognized high end shop.