Hello Andre
Yes, we had such a setup for quite a long time for connecting two routers back-to-back without a "leasedline" with serial-interfaces. It was somehow more a case of 'we have the interfaces already so why should be buy some new ethernetinterfaces when the cables cost not even 10% of the interface-price' than a 'there is no other way to do it' case tough.
But IMO such setups are more a lab-thing than real-live stuff in nowadays.