Things that behave different should look different. Transliterated mechanical models are always worse on computers. User interface design is not guesswork. User interface is not just skin deep. User interfaces that conform to implementation models are bad.
User testing can never substitute for user interface design.
Users don't make mistakes. Users get humiliated when software tells them they failed. Users make commensurate effort. Users would rather be successful than knowledgeable. Visually hint at compliancy.