It's worth keeping physical currency immediate needs in the case of a storm, earthquake, banking glitch, etc. (For most people, maybe $500-1000; the crazy thing is I know plenty of people who do nothing but use credit cards and just have $0-20, which sucks even if their bank just freezes their ATM account or credit card for 3 days!)
Otherwise, physical currency is exposed to the most serious risks (devaluation, inflation), plus physical loss, plus is relatively inconvenient to use. If you want a hedge against USD shenanigans, the things to do are:
1) Reduce ongoing liabilities (debt or expenses), particularly those which might adjust
2) Invest in income-producing assets which have pricing power
3) Potentially, hedge by investing in assets in foreign currencies or non-currencies, or assets in foreign countries, etc.
#1 and #2 are generally reasonable no matter what (buying energy efficient appliances, buying foods/etc. in bulk, education, being in good health, improving your skills, building products or companies...)