I think ptc sites are good if you do have a lot of referrals.
Exactly PTC Sites are good when you have lot of referrals then its good passive earning
I don't think so, because even if you have a lot of referrals, you can't be sure if you will get paid or not unless the site is an established one.
Still, there are no guarantees in this field because many PTC sites are just like HYIP schemes which come and go with time.