Here in the UK, there are bike thieves who will drive a van up to a bicycle park, load the van with as many bikes as they can get with some bolt cutters in a few minutes, then drive off. It would be surprising to see someone using a lock that allowed a bike to be carried away for this reason!

Of course it's mostly a problem at universities and train stations at night, where you can find big bike racks and no-one around. Lesser locks might be fine away from crime hotspots.