If you combine this EO with the Supreme Court immunity decision, there may very well be a situation where a rank and file employee acts illegally based on the president's interpretation of the law. This would create a situation where there is a legal challenge about whether a member of the executive branch should be granted the same immunity privileges as the president since they are an extension of the president. You can imagine where things will head if we end up on the wrong side of this decision.
At first glance, it seems like it's a positive thing for all members of the executive branch adhere to the same interpretation of the law. It's the definition of "arbitrary and capricious" if one executive agency interprets the same law differently than another. As others have commented, the president or AG's interpretation is still open to judicial review.