Aero bars in Grand fondos

Why are aero bars usually disallowed in gran fondos?
I’m just curious. I would think it would be a useful piece of equipment when riding 100 miles

Steering control is severely compromised when using aero bars. They’re not considered safe when riders may be racing in close proximity - a slight wobble could cause a major takedown. They’re not great for cornering either. Hence the reason they’re illegal in most events, except triathlon and time trials, where riders are mostly spread apart and riding fairly straight courses.

Whenever I used aero bars the handling was very difficult. I’m not sure if that was me not being used to it or the way they are.