If you're way into shaving weight and ultralight biking. This is not the lock for you. It's hefty, and would make a great weapon against potential bike thieves as mentioned above.
That said, it does a great job of protecting bikes! It's inexpensive, portable, and easy to take on or off.
If price is more of an issue to you than weight, then get it!
Update: After several months of use, I have to say I really like this lock. It's still heavy as can be, but definitely makes me feel secure.