Car insurance online?

Hello, I would like to buy a new car and would like to have some reviews, if it really makes sense to close the partial cascade online. Supposedly this is more and more the case, as you can read here: http://blog.geld.de/…/335609.html. Has anyone done this of you before? I am a bit skeptical, however, the favorable contributions are tempting! Is there a catch? Greetings