“…in early 2026, NASA decided to add an additional Artemis mission to the manifest. The new Artemis III would fly in 2027 as a near-Earth mission to test docking with whatever lunar lander (Blue Origin or SpaceX) was available. The first moon landing would be pushed back to the mission after that, Artemis IV. This change removed any rationale for flying astronauts on Artemis II.”

Is there truly no engineering or science merit to flying astronauts by the Moon?

For today technology, it's as hard as flying an empty crew module with all the live keeping equipment turned on. Add Buster from Mythbuster to get more accurate data about the forces on a human.

I think SpaceX used a piece of cheese in one of their test fliying arround Earth, just to show that the temperature was never outside a confortable range. They could have user the sensor they already had, but using the cheese too is good for PR.