I think it's more complex for government, but still complex for the person being questioned. For instance, the chart notes that if you are granted immunity, you cannot leave a form blank or assert your right to remain silent in a blanket fashion.
A second way things are complicated in the Hiibel case, which requires you to speak to the police to say your name.
A third way is that suspects who assert their rights are sometimes treated worse by the police. The US has a storied history of police abuse, including torture (Jon Burge, for one). Occasionally, this is caught on video, and it sometimes seems that the reaction by the police is one of anger. Infuriating the police by asserting your rights may get you some non-judicial punishment, including "contempt-of-cop", in which the police assault you and then charge you with assault via, for instance, bleeding on their uniforms (Henry Davis). In unlucky cases, you may end up dead from "excited delirium", a disease almost exclusively suffered by those in police custody but out of range of video cameras.
I'm not sure about that. The government does this all the time - cops will know exactly where the lines are and how to get you to fuck up. They get daily practice in it.
Meanwhile, your average citizen likely doesn't know what the Fifth Amendment means beyond vague stuff they remember from high school, and there's a good chance they really don't know you have to explicitly state you're exercising it.