We're used to viruses that have narrow cell types they can infect. Rhinoviruses can infect mucus membranes in the head and maybe throat. Influenza can infect the same plus lung tissue.
These coronaviruses can infect so many cell types. Because it's spread via the air, it almost always infects mucus membranes of the head first, then moves to lungs (or maybe it infects lungs first in some people). So we think of it as a respiratory virus at first.
Now we know it can infect tissues of the gut, fat, T cells, and the testes. There was a wave of orchitis/epididymitis that was discovered to be coronavirus caused. I'm not sure if it's considered COVID, I think COVID is the respiratory disease caused by coronavirus, but not sure about other diseases. Similar to how the varicella virus causes two diseases: chicken pox and shingles.