He3 may be on the list, but way down. Top of the list is jobs: Tax payers' money → SLS contractors in 50 states → campaign contributions → politicians' jobs
After a long gap there are other reasons, but the order is very subjective:
*) Flags & foot prints, national pride, look how cool we are.
*) Soft power: play nice with us and you can claim your country is making a significant contribution to Artemis.
*) For Science! - we will probably learn things from studying regolith.
*) Paper weights. Brag to your friends with one of these these really expensive Moon rocks.
*) Learn how to build Moon base: tourist destination and nation pride brag "First $Nationality person to visit Moon Base Alpha"
*) Learn how to convert regolith into solar panels, living space and oxygen for rocket propellant
*) Far side of the Moon radio telescope without all the noise from transmitters on Earth
*) Practice for Mars
*) Jeff wants tax payers' money for his rocket too
There are probably many more insignificant reasons but really only one stands out.