There are multiple forces at play. On the one hand, as you note, it takes time for people to die, which could initially bias the fatality rate downward. On the

There are multiple forces at play. On the one hand, as you note, it takes time for people to die, which could initially bias the fatality rate downward. On the other hand, a lot of milder cases will be missed entirely, which would bias the rate upward. My understanding is that the latter factor is considered more significant in the early stages of an epidemic like this.