The wallet, I feel, is not a practical wallet, just a nice to have. If you are a horribly organised person, it could be a very nice receipt or notes wallet so you keep them out of your actual wallet!
bionquo, it was said by many that they look like workhorse bags but they are really not. The hardwares on the bag are not able to sustain the entire weight of a fully filled large PS1. Saying that, my only issue with a PS1 is their hardware. They could do better if they improve the hardware to a sturdier one but on the other hand, it could change the sleek look of a PS1. The leather I have seen and felt is excellent, workmanship on the leather is great. The bag, on it's own, is a workhorse bag with such great leather and stitching.
I'm editing to add that Proenza has very good customer service. If you are intending to get a bag from them, you won't be disappointed with them. If your bag doesn't work out for you, I am sure they will try their best to help. I have witnessed some examples of their generiosity to customers and is very impress with them.