A reputable developer has a reputation to maintain (by definition), which makes Google's threat to permaban them a threat indeed.
A disreputable developer doesn't care about their reputation (again, by definition). They can create a new throwaway account every day and apply using the same (or slightly, easily, altered) code with different permissions every hour until they get permabanned, and start again tomorrow.
So the "obscurity" can be discovered easily through experimentation by the bad guys, but is still obscure for the good guys. This is not a good outcome.
Reputation can be bought too btw.
Malicious actors don't care about expenses nearly as much as benign ones do. So the point ought to be, if you want me to fix something, tell me what's broken.
1. age < 180 days
2. dau < 1000
3. some rule around user reports of malice on uninstall?
and this gets a bright warning banner on the top of the page, and it can't be discovered through the chrome store until crossing these thresholds.