I'm not sure how smart it would be to carry your valuables (i.e., credit cards and cash) in a wallet that you can't secure well inside a pocket. I mean, come on, even keeping it in your pocket is not necessarily secure since there are pickpockets who are known to steal wallets right out of others' pockets, but just clipping it to, let's say, on the outside of a jacket or backpack, is that really secure? Even if you put it inside a backpack, jacket, bag, etc., it will have to be something that you will wear or carry at all times, even when you are indoors or have to go to a bathroom. Women take care of this by carrying handbags that they carry with them at all times, but what about men? What do they wear or carry that can keep this wallet with them always (and don't make them look goofy, like a fanny pack)? Am I missing something here? I guess if you have a pocket that is deep enough, you can securely carry the smallest version of the wallet, but how deep would it have to be? Still, I'm tempted to buy one, just as a way to cleanly store and organize at home extra loose change and extra gift cards or credit cards that I don't want to carry with me for certain trips.
EDIT: I looked on Amazon and apparently, there are quite a few similar types of wallets being sold there. They are advertised as travel wallets, not necessarily the type you would use in everyday normal situations. If they are traveling as a couple, it seems that it's the woman who would secure it by carrying it in her purse. For guys, though, I'm still perplexed as to how they make sure that it is always secure if they are carrying it with them all the time. I saw a comment from one seller that said that it was meant to be carried in your hand, not in your pocket, if you want to always keep it with you, but I don't think that's always feasible. But I agree with one comment in a post below where the larger size might be useful as a way to organize and carry a tablet and cables/accessories.