For me personally the unknowns of such a new virus mean that the existence of the case studies would be enough to be concerned. And the strongest case is made by the fact that this virus' closest relative known to infect humans has caused lasting damage to people with cases that lead to hospitalization:
https://www.nature.com/articles/d41586-020-02598-6
"Evidence from people infected with other coronaviruses suggests that the damage will linger for some. A study published in February recorded long-term lung harm from SARS, which is caused by SARS-CoV-1. Between 2003 and 2018, Peixun Zhang at Peking University People’s Hospital in Beijing and his colleagues tracked the health of 71 people who had been hospitalized with SARS. Even after 15 years, 4.6% still had visible lesions on their lungs, and 38% had reduced diffusion capacity, meaning that their lungs were poor at transferring oxygen into the blood and removing carbon dioxide from it."
We know this much and SARS is poorly studied because it faded away so we generally lost interest in it. This virus is both similar and different enough to be very, very wide spread so even minor negative effects over the total population that gets moderate to mild cases will have the potential to have very large impacts on worldwide health.
As time goes on we are going to better document the consequences of mild and moderate cases and understand these things better, caution seems advisable until we do.
https://www.nature.com/articles/d41586-020-02598-6
"Evidence from people infected with other coronaviruses suggests that the damage will linger for some. A study published in February recorded long-term lung harm from SARS, which is caused by SARS-CoV-1. Between 2003 and 2018, Peixun Zhang at Peking University People’s Hospital in Beijing and his colleagues tracked the health of 71 people who had been hospitalized with SARS. Even after 15 years, 4.6% still had visible lesions on their lungs, and 38% had reduced diffusion capacity, meaning that their lungs were poor at transferring oxygen into the blood and removing carbon dioxide from it."
We know this much and SARS is poorly studied because it faded away so we generally lost interest in it. This virus is both similar and different enough to be very, very wide spread so even minor negative effects over the total population that gets moderate to mild cases will have the potential to have very large impacts on worldwide health.
As time goes on we are going to better document the consequences of mild and moderate cases and understand these things better, caution seems advisable until we do.