With the evolution of technology and mobile banking, we're relieved to never have to go back to that way of handling funds. Instead, we go on trips and handle cash just about the same as if we were at home. Withdraw pocket money from an ATM every few days so there's little to worry about, and put almost everything else on a credit card with no foreign transaction fees.
Now, having international bills in our wallet is more of a novelty than a necessity.
After getting robbed last month while biking in Argentina, we've had some time to reflect on wallet safety. Although the bandito only got away with our camera, he did make a try for our wallet. Even if he had gotten it, the most valuable thing would've been the wallet itself, a fact he would never have realized. Rob us 7+ years ago, and we would have been financially paralyzed in that destination.
What we're saying here is: get hip to traveling and using money like you would normally do. Get a credit card with no foreign transaction fees. Keep your card cancellation & help numbers written down in a different place than where you stash those cards. Download a currency translator app to your phone and know how much you want to take from the ATM before you get there. No big wads of hundreds which are supposed to last the whole trip and forget about traveller's cheques if you haven't already. Of course, exceptions can be made if you're heading out into remote areas or are paranoid that Big Brother is monitoring all your card transactions.
As always, the best advice is to use your common sense and be alert.