The Amazoness Quartet stole the golden crystal from Nehelelia when the Sailors couldn't which is VITAL in her defeat. The citizens and dreams that were
frequently dwelled upon during the season also came in handy as they were also VITAL in Nehelenia's defeat.
Also, I think the seasons message was to stop being a short-sighted selfish unempathetic piece of sh*t and remember that we need to care for the people around us as we all live on this Earth. Nehelenia's the antithesis to that. The Dead Moon Circus or a world where people are given shallow values ,undermine humanity and discourage others from growth or straight up take away other people's futures only thinking about them self is a dark dreary place full of jack*sses who do things for their own entertainment.
Also, with how the world is I think that's a pretty important message.
The Sailors can't do this by themselves. We need people all over the world to have a beautiful future. We all need to work together to defeat the symbolic evil that Nehelenia represents:
And lastly in desperate and vulnerable times never give up. Usagi after Nehelenia tries to take the most precious thing in all her world [Chibiusa] She didn't give up and tried her hardest to save her. [copy pasting] Nehelenia choosing selfishness and never growing up while goes into darkness [a dark future]. while Usagi chooses altruism and growth filling the world with light & hope [the solar eclipse going away so the sun could shine through after her brooch activated]. At least that's how I interpreted the ending.
TlDR: I think the season has a relevant message for kids.
If that doesn't really do it for you, you gotta at least admit it's one of the most aesthetically pleasing endings.
Also she fell for 4 minutes [that's still pretty bad but it wasn't 10 minutes]
