Why trust matters more than UI polish in fintech product design?

Spent the last few years working on fintech products and one thing keeps coming up: trust isn't a nice-to-have feature, it basically IS the product. Think about it. Nobody's "delighted" by a banking app the way they might be delighted by a fun consumer app. Nobody opens it for fun. They open it to check if their money is where it should be. Every weird error message, every inconsistent button style, every confusing flow doesn't just annoy people, but makes them genuinely nervous about their money. Had a cas