I was mainly attempting to stress that cold wallets are more useful when the stakes are high.
A modern phone OS will have plenty of extra weaknesses when compared with a security-focussed server/desktop OS. For phones, security (and transparency/openness) ranks far below concerns such as price, weight, size, spec., mass-appeal, ease-of-use, and being feature-rich. I'm reminded in particular of an incident where Android-users lost bitcoins, not due to any user or app-developer error, but because Android's SecureRandom function was flawed*.
If you do ever decide to manage serious amounts of money with your own phone app then please be mindful of these extra risks. Good luck!
*Note that this flaw was found because of Bitcoin. Bitcoin demands much greater security than most other information systems. Even a mobile banking app is less appealing to hackers given that profiting anonymously is more difficulty and bank transfers can be reversed.
I was aware of that flaw, i saw some friends of mine talk about that
But I am an iOS developer and because the sandbox environment that all iOS apps are obligated to run I am really confident in their security.
P.S.: Please I'm not saying that iOS is better or even safe.
Please do not take my opinions as anything elseYou have to understand it like this, cold wallets are like vaults they secure your bitcoin unlike a hot wallet. Imagine you have $100 in cash and you would probably put it in your personal wallet or let it laying on a table and that's ok since its not a huge amount of money. Now imagine you have $100k in cash , would you put in a bag ? Of course not you would need a vault to secure the cash. And that is why cold wallets are so important, if you are going to use small bitcoin amounts for daily transactions you will just need a hot wallet.