This is conservative, but also, this is happening in a very short time frame, AND is taking into account all of the social distancing AND is happening at the same time as flu.
Without the distancing measures we have in place we would be looking at millions of deaths.
Once this is over, it will be very tempting to say, "Look it was only as bad as flu, we shouldn't have trashed the economy just for that..." but that of course is not fair reasoning. We only will have 200k deaths because of the distancing.