I recall (dimly, I admit) that the magistrates in the Rhyl case were advised by the police that the condition of the tyres had no bearing on whether or not the driver lost control on the black ice, it would have happened even with legal tyres. I imagine magistrates typically take police information as gospel.
The condition of the vehicle will have been outlined to the magistrates as a matter of fact - the tyres were bald.
The relevance of that will have been outlined to the magistrates as a matter of comment - the bald tyres didn't contribute to the collision - which the magistrates can make of what they will, although they very likely accepted it.
One might ask why collision investigator mentions the tyres at all if they were not relevant, but it does give the magistrates an indication of the general attitude of the defendant to his motoring.
It also robs him of any mitigation along the lines of: "I am always very careful to keep my car maintained to the proper standard."
Clean windows is another one, I've heard investigation reports that cite the windows were dirty.
Again it might not be relevant, but it's another little dent in the defendant's armour.
The ever present possibility of a crash is one of the reasons why I keep my car well up together.
If I am involved in an incident, the investigation into me at least starts on the right foot.