It's bizarre that the Semi has way less attention than the Roadster on HN.
The Roadster is a $250k car for people with money to burn. It doesn't seem to drastically change the equation from a Rimac Concept One with six-year newer battery and motor tech and savings from volume and automation. The Roadster is the shiny thing that sells less sexy vehicles.
The Semi has the potential to change an entire industry if executed right. They don't need to be perfect if the cost savings are real and reliability is high. We'll see if they get practical details correct and whether production models arrive within 2-3 years of target-- a common Tesla worry. But I feel this has more margin potential than the Model 3 at this stage in Tesla's development.