What kind of site is this?

It ranks for random keywords and the ranking pages are pure spam Markov text. It gained all the traffic in the last month only. The site is not monetized with ads or affiliates or anything. So what is the purpose of this site?

There's an entire chain of these domains with .de TLD ranking for similar keywords and drawing in millions of visitors with spam Markov pages.

Those pages will look like spam when you access them directly, but if you find them on the SERPs and click through, you'll get redirected to a CPA smartlink. Check site:geibel-wilhelm.de, click on a result and you'll see what I mean.

Cloaking.
Old as Google itself