1, You can't goto your local petrol station or McDonald's to buy either cigarettes or burgers.
2. Do I really want to wait from 15 mins - 2 hours to confirm a small purchase at an establishment.
3. Sooner or later someone will crack private keys or find a way to control wallets and all Bitcoin will turn to dust.
4. How would you calculate the price of an item if Bitcoins price is so fickle
Isn't it the same thing if you show up in the petrol station holding a Japanese Yen while you are in Thailand? Same with going to McDonalds in Singapore and you only have Vietnam Dong with you. You need to go to an Exchanger to convert to local currency. ATM skimming is also rampant today which may endanger your life while withdrawing money from an ATM. The only thing that we hate with Bitcoins is the confirmation process which takes 15-20 minutes for the 1st confirmation.