so we agree, we all go nuts over how Benedick is the only one who believes Beatrice. but listen i've figured out why it's such a big deal. Benedick's choice to believe Beatrice goes against the flow of the entire play. it's not just a critical moment for them, but for the audience too.
to see this we have to look at how the idea of proof and belief crops up throughout MAAN. ("Prove that ever I lose more blood...", "Prove you that any man...", "... what was true and very full of proof.") basically: you want me to believe something? prove it. is there evidence of this other thing? yup, that makes it unquestionably true.
fair enough, right? but ironic in the context of MAAN, when you consider that all the "truths" in the play, with their accompanying "proofs", are fabricated. Beatrice wasn't almost sick for Benedick, and Benedick certainly wasn't in a consumption for her. neither was Hero a contaminated stale. yet these titular "nothings" are key drivers of the plot. why? because people thought they were "somethings". why? there appeared to be proof.
which is why it's so staggering that Benedick believes Hero's innocence — the crucial, the only, truth — without proof. in fact, all the evidence speaks against it. this turns the play on its head, because Benedick's choice is the exact opposite of the unspoken rule that everyone else follows: he disbelieves what seems to be backed up by evidence, and believes what has no proof at all. he actually does this on his own ("I do believe your fair cousin is wronged"), but what solidifies this belief to the point that it drives action is his respect for Beatrice's good judgement.
although this doesn't end up mattering in practical terms, it does symbolically mark the turning point of the plot. and the fact that Benedick trusts Beatrice's seemingly unfounded judgement over someone else's proof, effectively opposing the subliminal messaging in the play, speaks volumes of how highly he holds her in regard.
yes it's romantic because Benedick alone stands by her against everyone else. but it's more than that. he literally subverts the play itself.
I think I found my new favorite rabbit hole. This voice actor does Shakespeare scenes in a southern accent and I need to see the whole damn play. Absolutely beautiful