To prevent them from being registered out from under you.
There's two types of this form of domain kiting. They use the jibberish domains for cash parking because they only care about the link traffic not the seo, the more jibberish your domains are the less chance of being registered by others. The other is for seo traffic which uses actual offers and keyword domains (usually an exact match foreign tld) which focus on quick rankings. Both have their advantages and disadvantages.
The jibberish domain to cash parking method can be amazingly effective. You can also use feeds and cpc ads.
The post I made a few months prior to releasing the domain kiting guest post was actually playing around with it and it was the traffic source i was referring to in the introduction when I said I wasn't focusing on seo traffic lately (yet i screenshot awstats lol).
Blue Hat SEO-Advanced SEO Tactics Days Gone By For Traffic
I don't remember exactly how many domains those stats encompassed but it would shock you at how few (I remember less than 10 at the time of the screenshot). I also pulled a 20% ctr through to cpc ads/feeds with an avg of $0.20-$0.45 per click.