An 8th level a Life Cleric (I chose that because that happens to be the level of the Life Cleric in my game right now) can use channel divinity twice each short rest for 40 points each time, divided however they want among up to 6 targets, at range. And they could, if they wanted to, follow that with a bonus action 2nd lev Healing Word for another 13 or so hit points to someone else, and 4 hp to yourself.
That is a lot of healing in a single round. And I've seen it bring the front line fighter back multiple times (who normally, as a polearm master fighter with sentinel is dishing out two normal attacks, a bonus action attack, and a reaction attack each round, sometimes with a battle master rider damage on top of it). I've seen it bring two PCs back at once in fact, in the same round. And then all the damage those PCs dish out with all their multiple attacks should be "counted" as damage that Cleric did. Because but-for that healing, those PCs would be wasting all their actions on death saves (or, if they were not down yet, wasting their actions getting out of there or healing themselves).
Healing is like buffs. They're sometimes difficult to add up, because the benefit is "soft" in that it depends on what the ally does to see what impact it had. But it's pretty darn powerful when you do add it all up.