I agree with your smoothness example, but with consistency both "has" and "is" are common. Usage seems to vary by specific object and context. One example wher

I agree with your smoothness example, but with consistency both "has" and "is" are common. Usage seems to vary by specific object and context. One example where almost all authors go with "is": there are thousands of recipes saying to heat butter until it "is" a particular consistency, versus only a handful saying to heat it until it "has" a particular consistency. Compare https://www.google.com/search?q=%22until+the+butter+is+the+consistency%22 https://www.google.com/search?q=%22until+the+butter+is+the+c... vs. https://www.google.com/search?q=%22until+the+butter+has+the+consistency%22 https://www.google.com/search?q=%22until+the+butter+has+the+....