(a) resignation and potential replacement with someone else more willing/possibly less competent
(b) not resigning and maliciously complying
there are the matters of losing self-respect and peer credibility, opportunity costs of inability to apply effort and focus on something else more worthwhile when choosing (b), and an inability to criticize leadership.
With enough resignations and people speaking out, it adds even more to the mountain of evidence as a clear signal to reticent holdout, convincible non-ideologues.
It was never about any of the longstanding gripes or appeals to ideals - merely the lust for power and a siren song of telling people easy answers they want to hear. I say this as someone for whom Trump visited many things I care about in 2016 - I was the weirdo telling my aghast blue tribe friends that he had a good shot at winning. (I stated this in this direction, as opposed to the customary direction of "I agreed with Trump", because the latter is essentially undefined, as he constantly stakes out contradictory policy positions, often even in the same sentence)
(and to be clear, I of course wasn't foolish enough to vote for the guy. I don't even believe the hopium-lies of regular politicians, never mind someone who has the con artistry cranked up to 11)