Verify expected behavior instead of looking for bugs
Traditional testing is aimed at finding bugs, where a bug is defined as a mismatch between the specification and the actual behavior of the software under test.
JigZaw aims at making sure the system works as expected.
The difference may seem subtle, but there is a difference between the specification and works as expected. Works as expected is not one, precise definition. Instead it refers to the different views we can have on a system and that each test should focus on a single aspect. Works as expected has thus a very strong focus on regression-testing.
In other words, ensuring that functionality works is more important than finding deviations from a specification.