Why a plastic wallet? Well, paradoxically it can be good for the environment, but I like it for practical reasons. My money stays dry at the pool or on a boat---or in the rain. It pops into a zippered pocket easily on my shorts. And I don't care if it gets scratched up or something. If you want, you can even hang it around your neck on a lanyard, wearing it under your clothing.
The Jimi wallet comes in a variety of colors, is durable, is water resistant, and is made in the USA even, from 100 percent recycled materials. Get your own for $15.