For someone to get my wallet out of my pocket, they would have to hope I am rich, and then proceed to mug me. If I wore this, they could first check how rich I am, then decide.
When you pay someone with bitcoin cash, do you then wonder if they are going to see how much money is in your wallet and rob you, blackmail you, etc? Sounds like zero fun.
Phones are pretty advanced and widespread nowadays. Wallets can not just contain cash, but debit or credit cards. If you happen to have just exited your car, they may take that too.
And you'd like to add your Bitcoin Cash onto that as well? 'I'm going to take your car, your cash, empty your bank and oh I see you have Bitcoin Cash, I'll take that too'.