Originally Posted by Marco Esquandolis
The real question is if you can't get back into the raft without a ladder, are you in good enough physical condition to even be on the water?
It's not a question of if you can, it's a question of comfort when it's not urgent. It's hard for an average 120 pound woman to pull up, mantle, and climb into the raft. My lady is a buck ten, does pull-ups every day, and can definitely get back on the boat when she needs to. The ladder is because it's still difficult and she shouldn't have to struggle to take a leak or go for a swim in the flat water.
It also reduces the middle of the raft flop and giggle, which tends to get river water in my beer.