I find it interesting that motorcycle riders recommend cable locks while bicycle riders considers them the bare minimum protection due to how easily they are cut.
Motorcycles are ofcourse more secure than bicycles because the ignition and steering can be locked and they are much more difficult to pick up and haul away. A disc lock or a cable lock around an immobile object provide a second level of security. Each provides a different security that must be defeated an will therefore provide be even better when used together.
Best security is to use a high quality security chain or U-lock to attach the frame to an immobile object. These are ofcourse expensive, heavy and can be difficult to use. As with any type of security it is a matter of trade offs. Any system can be defeated, better systems take more effort and a higher level of sophistication.