I was very close to buying one recently, it was priced well below its pre accident value as well. It’d had a front end bump, no chassis or suspension damage. The seller had an engineers inspection done to help sell it. He picked up items such as odd wear to all four tyres, aircon not working, damage to exhaust down pipe due to impact, damage to sump due to impact, only one ignition key, engine noisier that you might expect etc.
It’d only done 1000 miles since the repair so it was the tyre wear that put me off. Plus the aircon won’t just be a re-gas after such a short time. He did say that the bodywork had been repaired to a high standard though.
So, I’d say expect to find faults (some of which might not appear for a while – like funny tyre wear) and always realise that it’ll only ever be worth what a Cat C car is worth.