I have a passcode to get into my phone, plus I have to use a password to get onto any of my banking sites, so it feels perfectly safe to me. I don't worry about credit card info being stolen because my credit card companies wouldn't hold me liable.
I don't worry about viruses. Are there viruses for iPhones? I didn't even know that was a thing. But I only download pretty popular apps and don't open random files on my phone, so I don't know how I'd get a virus even if they exist.
I don't, but mostly because I have a Windows phone with limited apps, and it seems to take forever to order something vs my computer, which is usually sitting right in front of me
I use the Mint app on my phone, and I deposit checks into my checking account via iPhone app. I generally do it at home on our secure network. I also have Apple Pay on my phone, and use the Starbucks app to pay for coffee and reload my Starbucks card.
I don't really shop on my phone, but that has more to do with convenience and ease of a computer vs. phone, than concerns about security. All of the above apps are locked with a thumbprint, password, or passcode.
My card information had been stolen a dozen times and it was never due to anything I did online. It's always been due to transactions in a brick and mortar store. If I were concerned about protecting my card information I would start by paying cash all around town.
But aside from that, there are federal laws that protect consumers from unauthorized transactions, and banks don't really have a choice when it comes to fraudulent charges. I've never had an issue getting things refunded and my bank refunds the account within 24 hours.
I suppose someone could get all my login information, but if they want to pay my electric bill they can feel free.
You can use two-factor authentication, so that an attacker would have to have access to not just your bank login, but your email or something else.
Of course usually the second factor is "your phone", which doesn't work so well as a security mechanism. Some banks will sell/give you an RSA keyfob.
The only shopping I do from my phone is Amazon, but I almost always "check out" from a computer. I don't do any banking from my phone right now, but that's not for security reasons.