Your question first supposes, incorrectly, that the current POTUS requires executive orders from prior Presidents to execute the Constitutional powers of his office. He does not.
Learn how the Constitution works and what executive orders mean.
The only purpose of this prior EO is political cover. It affords President Trump no additional powers beyond what he already has. He could write the same order himself if he so chose. It's FUCKING EO, so of course he can.