Although it is true that many tourists visit Laguna Beach, given its population is only ~20K it wasn't considered a population center of inter-regional importance (although it looks like it was listed as a potential borderline case). https://osm.wiki/California/2022_Highway_Classification_Guidelines

The US community has also been trying to form a more coherent network of motorways and trunk roads in recent years, and avoiding spurs and islands of these classifications as mentioned here:
https://wiki.openstreetmap.org/wiki/United_States/2021_Highway_Classification_Guidance#Classification

Because of this, I think it's best to leave Laguna Canyon as primary  before further discussion with the community.