- To carry my wallet+phone+keys, it will need to be reasonably sized - To be trusted with my wallet+phone+keys, it will need to be durable- built out of leather, or at least something like heavy canvas - It can't be brightly colored or otherwise goofy, because aesthetics - If you're wearing something on your hip that is dark-colored, made of heavy-duty material, and is roughly holster-sized, it will generally look like a gun holster to casual or distant inspection. That's not only a bad fashion statement, that's plausibly dangerous in some circumstances.
A pouch mounted right above the knee might solve this (I don't think anyone wears their pistol there?) if there's a decent way to wear a pouch that's not hung from the belt.