There are several things that will make one option better than the other. Nothing says you couldn't use the weaker option and still catch fish but just that one is better than the other.
The two main things that make a difference between the two (to me) are current and abrasion resistance.
If you have ever fished in a swift current river, you will have found that the current will push your bait way down stream. The current is pushing on the bait but also on the line. Since braid is much smaller in diameter than an equal strength mono line, the current has much less effect on it. Now you don't always have to be in a river to get the same effect. If you are dragging baits in a lake, you pulling your line and bait thru the water causes the same effect as current from the river. It has the ability to lift your bait up off the bottom. Maybe not to the surface but much higher in the water column, taking your bait out of the typical strike zone.
Now braided line, has a much higher breaking strength, so you get a much higher tension strength with a much smaller diameter line. But one of the weaker points of braided line is that it does not stand up to abrasion well. Rubbing on anything abrasive will cut it much quicker than it would mono line. One of the big issues on rivers that have been dammed up is that the original river bank is now way out in the water so when you cast your line from the bank it goes out thru the shallows but then sorta drops off of a cliff, as it goes over the original river bank/ledge. Here in eastern Tennessee, we were blessed with an abundance of rocks so when you reel your bait back in, you are forcing it thru all those rocks at the crest of the ledge. That is very abrasive on your line but mono line will stand up to it better.
It is not as much of an issue when fishing from a boat because you often fish parallel to the ledge so it is less of an abrasive problem.
Now if you have ever had a big cat clamp down on your hand or finger when you were trying to be so kind by removing a hook, and because he bit down you yanked your hand/finger out , you will have an idea on how abrasive a catfishes sandpaper teeth are. That is why some folks just use mono line or at least a mono leader. It is also why the mono leader is usually 50lb test or higher.
There are reasons like one line will cast farther than the other or one lays straight while the other twists up into knots but I will leave that for another day.
tight lines all