I guess I just don't want to install plug-ins on every browser/computer I use, since I have a lot. Plus work, library, friends' computers, etc. Memorization comes in handy at that point. As for typing, it's not like typing in even a 18+ character password is that slow.
With iCloud sync now, all you need to memorize is your Apple ID password (to install 1Password from the App Store and have it sync from iCloud) and your 1Password password and you can bootstrap your whole password database onto every computer you own. Typing 20-30 character randomized strings is something I try to avoid. What a pain in the ass.
