I agree with Emily. You only need one secure money/card storage system. If you have a secure travel purse or bag, and are not the type to be careless with it (don't sling it over restaurant chairs, don't set it down while you take a photo, etc...), then place your wallet (s) in there. They key is that the bag must be a secure travel type bag, not just a purse that unzips from the top like normal. Secure travel bags require several steps to gain access (typically with inner secure pockets) and can't easily be accessed without you noticing (and you'd be amazed at what a pick-pocket can do without you noticing).
Or you can use a moneybelt, which is not convenient for accessing and forces you to use a regular wallet for that day's money. Or a neck pouch, which can be easier for you to use. Or a belt-loop wallet that is very easy to use. All three are equally secure from thieves.
Also, there is less of a concern of accessing your money/cards in public as there is keeping it nearly impossible for pick-pockets to access. That's why you use a secure system - not to hide it from thieves.
Leave other currencies back at your hotel in the safe or in your luggage secured with a travel lock.