It makes it easier to target the person with Scams, Fraud etc. With one glance I can tell that Markel is of Dutch origin, lives in SK, Canada, might be a student or works at U of SK, banks with <...>, maybe works at <....>, is into bikes etc. They were in Japan in 2012.
Putting all your bookmarks public isn't a great idea, but it makes OSINT (open source intelligence) a whole lot easier. This was just five minutes. And I hadn't looked at the whois yet.