Great to swim in, I suppose. Nothing like yards of cloth to weigh you down. Once you get fatigued from the weight, I'm guessing only your husband or relative is allowed to rescue you.
My mother was going to an apostolic church for a while. They would rent the entire pool so that women could swim without men. They had to swim in blouses that went up to the neck, and ankle-length skirts. Not much difference here, and this is a christian church (although there are some - myself included - would dispute that).