One thing that happens doing this, is that the most important passwords are the ones I type the least.  The least important passwords get stored in the web browser**.  I could use throwaway random passwords for this, with email recovery if I lose it from the browser cache.  It’s also really really important not to store high-security passwords in your web browser, and this scheme discourages doing that.  You don’t store a higher-security password in a lower-security one.  Your web browser history is less important than your bank account.  Browsers and OSes get compromised by bad people, and you don’t want to let them at your most important stuff.