As I understand it, normal flour with gluten is perfectly healthy, unless you suffer from celiac disease, and perhaps some other syndromes.
For people with celiac disease, gluten free is a must. It can be pretty bad otherwise. I have a good friend who has a very rough time with celiac disease.
But many people who insist on gluten free are doing that because it is the newest fad, not because they have celiac disease.
https://www.youtube.com/watch?v=Oht9AEq1798