If they are in specialized containers with elements all from earth, they aren’t really seeding another celestial body.
A person posted on an earlier thread, they could have done this on the space station.
Agree with your comment with the caveat that growing the plants on the Moon would probably provide useful locale-specific information on the amount and strength of sunlight, received radiation, etc. The always Earth-ward face of the Moon has an electromagnetic spectrum environment that is different from the earth-orbiting space station.
On a completely silly note, I am glad to see no kudzu seedlings are in the experiment. Not a pleasant thought to imagine discovering that species could survive on the Moon. Even worse if it escaped containment.