Sure, novel is a sliding scale. But it has been novel enough for our immune systems, and that is sufficient reason to be cautious. Also its epidemiologic profile was sufficiently different that our knowledge with sars or mers didn’t help us being in a pandemic right now, which can’t be entirely explained with bad policy decisions.
I'm no expert. But I am reticent to think that sars/mers and covid are going to have similar long term effects. Mostly due to the strange additional symptoms with covid that don't appear to happen with Sars/mers. Loss of taste and smell is one of them. Infected and inflamed extremeties is another. It seems as though covid is more adept at infecting other types of human tissue rather than just respiratory. Which on a micro level might be a rather small difference but could have very serious long term differences in outcomes.
Obviously we can't just sit around for years and wait for evidence to appear. We'll have to move forward based on incomplete information, knowing that some of it will later prove to have been wrong.