Yes, in fact they are. I can store my credit cards on my phone, but I still have to carry around my id cards and it's annoying. I have to take my phone and I'd rather not take anything else.
Having only one thing to lose (actually two including my car key) means that I might actually be able to keep track and hold onto it. It's a real problem for the absent minded.
Inconveniencing yourself due to some vague paranoia about government is for the tin foil hat crowd. Here in the real, rational world you need to carry your driver's licence and your id card to get things done.