A lot of time heuristics won't work on very common website, including this one on the sign-in page or Reddit, sometimes when the native password manager does the job, meaning you have to go into the extension, input pin and do it manually.

Then there's the fact that when doing so, a lot of the time the extension won't automatically save password or login as-created because you didn't confirm creation after generation, which is redundant and an unnecessary step?

Also, it's a bit complicated to update or add field once an entry is created. I cannot edit the current entry to add the associated username for some reason.

Finally, this goes with the most requested feature to be able to merge duplicates or group by domain. Registering to this website was so oddly complicated that I know have 5 entries and have no idea which one is the right one.