Properties are meant here as defined in Cheng Lou's talk - optimization, analyzability, hackability, readability
examples simplify adoption of technology - Examples, allow you to look at the system from the more concrete/less abstract standpoint. Allowing users to more gradually comprehend the overall system
has a bit of a different meaning here vs how it's used elsewhere, I think
making a language explicitly non-Turing-complete allows you to easier analyze the code/data in it and ensure that it's safe/optimize it automatically/etc
another discussion on this https://www.gwern.net/Turing-complete