Flu deaths occur in approx. 0.1% of the cases. Plus, there is an expensive medical infrastructure to deal with the worst flu cases.
In Italy, the corona virus is deadly in around 7% of the cases.
One of the worst things about the corona virus is that you are contagious up to 5 or 6 days before any symptoms appear. Making the spreading of the virus much easier.
Also, the reasons we are closing businesses, large venue events and the like is because if we don't we will end up with the same situation as Italy has. Our medical system will be completely overwhelmed.