Yaarel
🇮🇱 🇺🇦 He-Mage
It's not modest.
Compare it to the other healing available.
Take it at level 1 you have a single hit dice and the cleric has two spells. Healer feat is roughly a cure spell that scales.
4 PCs 12 uses
5pcs 15 uses
6 PCs 18 uses
Assuming the two shshortirt rest thing. Healing kits are cheap enough.
It's the most borked feat a varient human can pick.
When the Healer feat wastes the chance to attack during combat, in order to heal an ally, then it is modest.
If every one of the 4 PCs are going down in every encounter every day, then the players are doing something wrong.
The feat itself is modest.