For savage content healers in general are supposed to avoid having to cast GCD heals like Physick, Benefic, or Cure as much as possible, but they do end up needing to be used sometimes as we learn fights and especially when we don't outgear them yet. Full optimization is not really the goal during prog so you may need it sometimes.

For SCH yeah you are supposed to avoid using Physick as much as possible. Supposed to heal with your other tools like Excog/Lustrate or even Adlo and fairy stuff while doing DPS where you can. Physick for SCH is just a bit weak so it is generally deemed as a waste of a GCD since you have better options usually.

Even still I still keep it on my bar.