No they ruined reputation by destroying the security model and economic incentives in bitcoin. They could have prevented an attack with hash power - instead they corrupted it all.
No they made the chain more secure, and Economic incentives? You are good at making shit up.
more secure? REALLY???? With only 10% of nodes accepting the CPs every 10th block it is an almost certainty to cause a permanent chain split if publishing 10 empty shadow mined blocks
You publish the 10 blocks right at checkpoint time and 50% of network go with the 9 original blocks and it gets checkpointed by some ABC nodes and the other 50% checkpoint the reorg