I felt like I got duped into revealing my Facebook account for no reason. The page indicated that I'll 'save time' but as far as I can tell I didn't save any time at all.
Quora uses your Facebook friends graph to determine who you'll initially follow on Quora. It's been critical to onboarding new users and showing them relevant content immediately.
for me its clearly a reason to not sign up with Quora...
It will save time every subsequent login, because you won't have to type anything.