Originally Posted by
meanwhile
If your insurer is satisfied with that, great. But such a lock can't work better than its chain, and any chain you can reasonably carry with your can be cut in seconds.
Here in the Netherlands bike insurance is offered through your local bike shop (coupled to a large insurance company). The only requirement needed for bike replacement are the two keys that came with the (usually pre installed) ring lock. That's just how it's done over here. Almost all bikes have the ring lock installed. (As a point of reference, there are 400,000 bikes stolen every year here in Holland.)
I have an Abus U lock mounted on my bike and sometimes use it though since my bike is insured, I really don't have to. In many large Dutch cities we have free guarded parking for bikes. This is a relatively new development. (I know first hand that Den Bosch and Eindhoven have free guarded parking for bikes.)