Healing Sphere is a good spell for some situations where you need a little "Backup" heal if you wanna say so.
let me give you some examples:
Sha of Fear (tank @boss, not @pagoda): it's important to keep the tank at 90-100% life all the time, and for that it helps to place some healing spheres under the tank which will be instantly heal the tank if he gets a high amount of damage.. of course on that fight the tank should use his own def cd's and stuff to protect him as good as he can by himself, but you will have to do a lot of healing too. (don't be afraid of going OOM, every 1:30min you teleport to the pagoda and can grab the bubbles to get your mana back

.. so going down to lets say 10% mana on Sha is ok, cause you will easily be at 100% mana in the pagoda before you go back to the sha place)
Garalon - the healing spheres will here help you to heal the pheromones kiting player a bit, while healing the group/tanks. just place 1-2 in the way of the kiting player and he will be fine. and what i do: when i take the pheromones i instantly place a healing sphere in front of me, because you can make 1 step and then the crush comes. the crush knocks you down and if you are unlucky you will lay in a pheromones field. so the healing sphere helps you to get you on a good amount of hp to stay alive when laying in a pheromones field because of the crush.
and yeah.. there are many other really usefull situations, but i prefer to place them manually. and i don't really see a need for autom. placing by the cc.
but that's just my personal preference
e: i do both in our raid, group+tank healing. a good mix