I believe there is. Neither you nor a home inspector can see through the walls. If the electrical wasn't permitted and inspected, how can you know whether or not it was properly done. Same thing with plumbing and gas. As to the bedroom, is there legal egress, and if there is and an enlarged window was installed, was it done correctly or was the structure compromised?.
I'm a contractor and I've seen enough unpermitted work (usually done by homeowners) that is poor practice and even unsafe to scare me off.
My wife and I are currently househunting ... when I come across one with an unpermitted finished basement, I value the basement development at minus three thousand dollars (the cost of tearing it out).
Ken