The main reason is to avoid piling too much on top someone that may already have their hands full. In my experience with startups, this is most people's first pool, first exposure to chemistry, acid fumes, pool equipment, water testing, etc...and add a pregnancy, a bus full of kids and an unconventional startup method on top of that!
The pucks are very easy. They slowly add chlorine, CYA and a little acidity. This prevents exposing fresh plaster to too much chlorine too early. The other issue is that many colored plaster mixes come from organic based pigments which are susceptible to being bleached out, blue being one of the most prone (which was also confirmed by OnBalance through testing).
CYA is somewhat complicated to add for a new pool owner, and testing may be even more difficult. I'd rather see the focus directed at maintaining the pH and TA since those numbers are so far on the high side of things during a bicarbonate startup and damage could occur if left unattended. I can't imagine getting scale on brand new plaster.
Rather than having Jaime raise the FC to 3 just to do an OCLT, I think it would be best for her to add enough liquid chlorine to get to 2 and maintain that for a few days since that is about what shock level would be. I still can't imagine that something could be growing in the pool since it hasn't ever been without chlorine and the CYA started at 0. Her tap water was also very high in chlorine if I remember correctly which makes this even more puzzling.
You are correct that now that two weeks have passed, it would be fine to add CYA and begin maintaining a more appropriate FC/CYA level.