This Is Good Information
I have personally repaired 3 of my cars that fit what you describe. Two were hit in the rear and one in a rear door. They were totalled by my insurance company because of their age and value. I bought the “salvage” from the insurance company by their deducting it from my settlement check.
I repaired them and kept them solely because nothing “mechanical” was damaged. They drove just fine immediately following the collision and I knew the car. I did this because it involved only body damage and I did some/all of the repair (on one car it was all bolt on and tap on work) or had a professional do repairs. The car that was hit in the door got a like new salvage yard door for $90 that I installed and a body man fixed the 1/4 panel. The car hit in the rear needed rear bumper brackets, used front bumper and a smack on the tail panel from inside the trunk. These cars all passed my insurance agents inspection and had collision coverage reinstated.
Had these cars suffered “mechanical” or frame rail damage (safety issue) the salvage would have belonged to my insurance company.
That’s how I look at repairing totals.