Hard to work a horse off leg pressure when you have split reins?
I trail ride in either. I prefer gaming/roping reins for novices so that they don't drop a rein. But I view trails as another opportunity to school my horse. Open areas we may do some lope circles. Much easier to isolate his shoulders or hips if I can manually move them with my legs and reins.
No, but I usually set my reins on the horses neck, and my split reins always fall.