It won't be your property forever, and future tenants have a right to live in a place that was constructed safely. I'd rather not find out that the wiring of the house I bought was installed by an unlicensed amateur when it burns down the house. That house fire could also spread to your neighbors, so it's not just your property that's at stake.

I agree that some permitting requirements can get out of hand; for example, some jurisdictions require a permit for repairs as simple as replacing a kitchen tap. But I'd rather the law be too stringent in this regard than too lenient, and it’s easy enough to flout the law for simple things like a kitchen tap.