This can be true, especially in 6-man group situations. Of course, if you're a melee divine, quicken is non-negotiable, but if you're a caster, there are indeed situations when it can be turned off.
However, this seems to become less the case in many epics, where the reaction time is absolutely essential, and it also opens up the use of the most mana-efficient heal spell, Mass Heal.
So yeah, a time and a place, and all that. You just need to recognize what a situation means. And I agree that concentration is a must, as heal scrolling reliably is the only thing that makes some of the more attrition-style epics affordable in terms of consumables (thinking mainly of ECoF, EDA, or EADQ1).