Some kids never rip, some kids cannot keep any skin on their hands even when both are doing the same workout. I personally as a gymnast ripped maybe 2-3 times in my life, two daughter gymnasts same thing. I have 4 gymnasts in level 6 who rip every practice even with grips.
We do not have our level 4's or 5's in grips but have some palm guards that they can use for a practice if they need to. I do not want to be continually making grips for our level 4's so we just keep a pair of palm guards around and if they really need to they can wear one or both during part or all of practice.
I would say our habitual rippers fall into 3 groups: the seriously sweaty, higher weight to strength ratio, and the ones who use a death grip on the bar. If she is the first 2 groups, palm guards may be a help to her. If she is the latter group, the coaches need to help her adjust her grip.
Also be wary of playground bars and the metal home chin-up bars. I see a lot of ripping on the girls who like to swing metal bars outside of gym.
If her gym recommends it then as a parent I would take the middle road and buy the palm protectors and ask the coach if they can just be worn when she has a rip and have her continue to work bare-handed the rest of the time.