That's an exam cramming technique regardless of handwriting quality :)
I find this slightly amusing/ironic because many (most?) fountain pen inks are not waterproof. I had a sheet of paper that was full of (fountain pen written) writing on my desk when I spilled a glass of water -- after the paper dried there was hardly any evidence that there had been writing on the paper. I know that's not the parent's point, but something turned in that was written with a fountain pen would be easier to remove: a teacher would just need to dunk the paper in water!
I assumed this was for child friendliness - you just know kids are going to get ink on their fingers etc while changing cartridges from time to time.
I was curious about this so I just did a quick non-scientific perusal of one fountain pen enthusiast shop's offerings. It shows 118 of the ink bottles they sell are water-resistant ink while 935 are not (looking at the Yes/No filter counts for "Water-resistant" at https://www.gouletpens.com/collections/bottled-ink). There's a lot of duplicate inks that can be purchased in multiple bottle sizes, but picking the three most represented bottle volumes (20ml, 30ml, and 50ml) it drops to 24 water-resistant inks and 578 inks that are not water-resistant.
The above includes a lot of "interesting" colors; further restricting to black ink only ends up with 3 that are water-resistant and 26 that are not.
In Slovenia, back when I went to school, we all learned with fountain pens and cursive. From 1st to 8th grade you were required to write in fountain pain. If you turned in an assignment written in pencil, it was legit for the teacher to use their eraser and give you an F for turning in empty paper. (They never did this but threatened it a lot).
As soon as high school hit, the restriction lifted and we could use any utensil and whatever font as long as it was legible. Everyone switched to ballpoint pens and some bastardized combination of print and cursive.
I still use my specific combo of print and cursive today, it's like encryption. Very fast to write, very slow sometimes impossible to read. And that's okay, it turns out that anything I write down by hand gets etched into my memory forever. Just seeing the rough shape of the letters brings it back. Sometimes just seeing roughly what page of my notebook it's on is enough to remember what I was thinking.