Question: what game do healers "just heal?"

I cannot think of any game I have played, MMO or single player, where I just spammed healing spells.

The closest MMO I could think of where you just "only healed" was FFXI. But... counting on the job you were playing, you were still doing something when you could between healing: Whether that be debuffing the mob, buffing the party, or /heal to slowly gain by HP and MP.* You didn't just spam cures.

*In FFXI, there was no passive HP and MP regen. You have to use the /heal command (Or [/] key) to go on one knee and slowly build back HP and MP. You could not do anything else. Getting hit or moving canceled the regen.