When you're saying "set a sync password", is that to replace 1password? I've always stuck with the "pass" cli tool to handle my passwords, but I'm now thinking of making the switch to one of these browser based tools, obviously because I can't do cli on Android.

The sync password encrypts everything you sync via Google servers (incl e.g. settings and favorites). It also encrypts the password manager if you choose to use it. I recently moved most my passwords from passage to 1Password to get browser and mobile support.