Indeed, but they are effective enough to bypass the need of a healer. The existence of Vulne stack, dps some time getting killed after a simple mistake and dps being able to rez and 3/4 tank having access to almost on demand healing just create a situation where the only difference between bringing a healer or anything else (assuming no healing check mechanic) is the lost of a Healer LB and a slightly smaller ammount of mistake the party can make (and good chances of having a smaller ammounts of rez user in the party)