Healing away plot points

I think it's ok in that case because she takes a huge toll on herself and could possibly die because of it so she could be in a situation where she can't help someone precious because she already healed someone else which could be quite interesting I think ^^

As Namliss mentioned, it will take a toll. I believe we will see later on how much it will cost and the complications around it. In order to safe one like that, Estelle will suffer quite bad I think...

If you remember it isn't just the toll however, the breed of a spiritualist itself is very rare and she's the only one. (Explained in previous chapters before she ended up with Alpha and them) Each time she uses her power, it's like losing part of herself/soul. Ultimately she is doing good, but she's slowly killing herself by using her powers like the previous ones before that disappeared.

especially with female leads because they need to stay pretty

Same goes with male leads, though not always. In the end, everyones gotta look pretty or else they have no right to be part of the story.

I agree, in this story specifically this trope is being used relatively well. And as you said, if the author chooses to do so she may end up in a dire position due to her limitations.

I guess I was speaking more in general about how health concerns are dealt with in these stories, especially with fantasy elements.
A lot of stories bend over backwards to avoid disabilities of any kind that can't be made "fashionable" or be part of a love story. A lot of mental illnesses are "fixed" by having the character be "cured with love" and physical disabilities are never treated like disabilities, just a new fashion piece. "Phantom limb? Chronic pain? What are those?"
And aside from being a ableist standpoint, it also means that no meaningful character, especially a character on the side of good, will die. It robs a lot of tension from scenes that should feel tense, or robs a lot of the relief you may feel at the end of the fight.
It just feels like such a cheap trick to use, and while healing powers are not bad in and of themselves, I find that many authors don't use it well.

its not always as important for male leads, they can have a scar or missing limb and he can still be the hero that slays the dragon, it gives them an edgier more mature vibe. from what I've seen the only times they use a scar or burn for female leads is to empathize how pitiful they are. most of these shoujo webtoons focus on above average conventionality attractive FL's, looks determine worth for woman (both today and in those types of Victorian style setting) and is often times the only thing empathized about her character aside from a good personality..