Well so far the statistics show
Regular flu spread is 1 person spreads it to 1.3 other people
Corona is 1 person spreads it to 2.5 people, so about twice as infectious
Regular flu kills .1% of those infected
Corona kills 3.5% depending on medical services available, so 35 TIMES more deadly with no medical services, but still 2% with medical services
Yes in a health person symptoms are mild, but that's a BIG problem. someone doesn't feel that sick, so the spread rate goes even HIGHER
This "bug" is reproducing faster BEFORE showing symptoms in the host(us), an evolutionary advantage before killing the host