I can't create a backup of my cash.
I've never lost cash in my life. I guess my money means too much to me to be careless with it.
I can't protect my cash with a password.
I have a CCW. I protect mine with Smith & Wesson.
I can't transfer my cash to merchants that I want to do business with over the internet.
Debit Cards are electronic cash and come with fraud protection.
My cash will suffer the effects of supply inflation from the Fed overprinting it.
Bitcoins exchange rate can crash through the floor at any moment and you'll never know when.
Carrying or storing large quantities of cash take up more space.
See Debit Cards above.
Cash is generally dirty and has an increased potential for carrying bacteria or a virus.
Just like I tell my kids, don't touch your face when you touch a door handle at the mall and wash your hands before you eat.
Do I need more reasons?
I guess you do. LOL