But...I...I don't wanna DPS, I'm a healer...

[Lyrica_Ashtine]

Here is the thing. Every cleric stance CD puts you in a vulnerable position. During this time situations can happen that lead to failing your main priority - healing.

This should only happen if you are unfamiliar/lacking experience with the duty. Obviously, you shouldn't be going into Cleric's Stance when a big, potentially tank destroying attack is coming within a few seconds. It's a matter of knowing or doing it often enough that it becomes muscle memory. But that all takes (a lot) more effort and maybe that is the "scary" aspect about it? :P
But this is a form of effort all jobs have to perform for harder content

[Cynfael]

This should only happen if you are unfamiliar/lacking experience with the duty. Obviously, you shouldn't be going into Cleric's Stance when a big, potentially tank destroying attack is coming within a few seconds. It's a matter of knowing or doing it often enough that it becomes muscle memory. But that all takes (a lot) more effort and maybe that is the "scary" aspect about it? :P
But this is a form of effort all jobs have to perform for harder content

I just want to second this because it's important.

Lately I've seen CS mentioned by other posters as if it were some sort of roulette that put party members at risk of dying in exchange for increased DPS potential.

As Lyrica suggests, CS is not something that healers spray-and-pray with. It should not leave you vulnerable since you wouldn't have toggled it on (for a whopping 5 seconds at minimum) if life threatening damage had been imminent.