Plus, at least for Safari, it's only protected by the computer password, which is much less secure than the kind of pass phrase that password managers ask for.

Plus, at least for Safari, it's only protected by the computer password, which is much less secure than the kind of pass phrase that password managers ask for. My mother-in-law has her computer password on a post-it that is stuck to the monitor. Using that, I can go into her browser preferences and see the plaintext value of all her browser-stored passwords. I never use it, myself.