The same benefit as when used with a curb – the horse can “feel” your reins more if there is more weight to them.
More feel = rider able to cue more subtle
If they are a little heavier and wider they are easier to hold and you don’t get a lot of unneeded movement that can be an issue if you are not riding with full contact all the time. Not taking the really heavy ones that weight a curb bit, just not floppy little skinny things.
You definitely don’t want to go trail riding with closed, loop reins, you need split reins so they don’t catch on the horn and nobody puts a body part through them in a sudden spook,
Reins have their uses depending on what you’re doing and what bit you’re using.
@BlueDrifter, if you’re riding in a snaffle bit typically a browband headstall with throatlatch, a chinstrap on your snaffle and split reins or a McCarty with slobber straps would be appropriate. Unless you’re barrel racing or roping in the arena, then those style of reins would be fine as well. Outside of the arena I find they are too short to use.
A lot people don’t like the feel of a horse hair McCarty so of course there are other options, mainly yacht rope.
good luck
I won’t use snaps on reins. Would you like the metal on metal clanking in your mouth? There are so many quick change reins and headstalls nowadays, the need for snaps isn’t as great.
I like heavier duty split reins for snaffles. I use split reins on all of my horses. I like the ability to give an excessive drape if needed.
