Considering the article is about the UK, I'm not sure how relevent US utilisation is in relation to it.
That aside, I didn't say low utilisation, I said no utilisation. This has a good chance of your card being cancelled by the card issuer, which has a negative effect on your credit.
Bottom line is, unless you plan to use the card, there are better methods of increasing your credit score, so it's not a good idea to get one.
