The advantages would mainly occur in the social and material spheres.
In the social field, that many girls began to wear it would be positive for those of us who currently wear one. I am not ashamed and I believe that if I saw myself in a situation in which a third party noticed the belt, I would know how to get out of the situation with ease, but it would not be pleasant, for comparison, we are all careful when we wear a skirt, but if I am not careful, no one is going to think anything strange about seeing our panties, with a belt it is different. And the truth is that, at least for me, I occupy my head more than I would like to think of combinations and ways to hide the belt.
With more girls, this would disappear.
A few days ago I explained, here the behavior of many of my colleagues at the university is shameful, some of them resemble animals in the reproductive season, which perhaps at a biological level is not inaccurate. With a generalization of the use of belts, their flirtations would surely be calmer and, incidentally, their search for a partner much more careful, which, at a biological level, is also much more effective.
Being able to go places with the belt as Sara has said would be fantastic since it would save the need for breaks and the tension that comes from managing that freedom that in principle we should not have, even for me who for a long time had the belt more time in the closet that on my waist.
In my opinion, in principle all women should wear a chastity belt, I think it is something that helps us commune with our feminine essence and, in general, makes us happier. But, the truth is that this in the real world, does not happen. Each woman has a series of circumstances and many reject this and forcing them not only seems useless to me, but it would also create enormous and unresolvable conflicts, within the families and see the girls' background as well. If suddenly the number of women with chastity belts increased voluntarily and even enthusiastically, I think it would be fantastic and it would value a much better and less toxic model of women for ourselves.
On a material level, of course the design, not only of the belt that should be more combinable and with the possibility of aesthetic decorations, brooches, bows, but also the availability of clothes already designed for it, summer dresses, pants, nightgowns, summer pajamas shorts with velcro for thighbands, the options would be endless.
The metals of the belts themselves could be different as there would be more interest in their development, there would be more designs...
And I am sure that if I put something else, more advantages would occur to me.