As somebody that enjoys leveling all jobs to max and playing all of them, healers are my least played.

Why? Because its the only role where your gameplay is tied to party incompetence, meaning the amount you heal depends on how much tanks suck and dps ignore mechanics. If party is competent then the gameplay loop is quite boring one button spam.

For non-static play this is toxic relationship. Meanwhile if healing in statics its essentially "optimizing the fun away" as you minimize healing you do for your one button spam.

At least with tanks you have some semblance of rotation so after optimizing mits you still have gameplay loop to keep brain engaged.