For example, you say "cancer" and everyone has an idea of what that is. As of the 2000s/2010s, awareness has been rising about mental health and what it actually means to have mental illness. But if you say "long covid", most people still don't know what that really means to a sufferer of it. With its relative commonness compared to other, rarer yet more well-known illnesses (like DID), I'd say it deserves more attention than it gets.
If we think of public disease messaging as having limited "bandwidth", it makes sense to message about the most common, newest, and least understood diseases, wouldn't you agree?
The more the public understands what having an illness means for its sufferer, the more understanding the public will be of that person's needs and limitations, and thus the fuller a life that person will be able to live as their limitations are accommodated.