It's most likely the opposite. People have no idea how to keep their desktops/laptops secure and it is much worse then it comes to the mobile area where apps can have access to almost everything. Another problems would be apps that carry hard to remove exploits (tends to happen in android). It is not possible for a smartphone to be safer than a Linux machine solely dedicated for a wallet, running behind a hardware firewall.
Well a while ago I was talking about using an android phone as a secure wallet, it can be done and cheaply.
http://www.walmart.com/ip/Straight-Talk-Samsung-Galaxy-Ace-Style-S765C-Prepaid-Smartphone/36202742#about20$, dual core, has a microsd slot. All you would need to do is not use it as a phone, sideload a secure electrum apk, generate a wallet and send your coins to it. Using it as a secure wallet and only using a known wifi to send funds off and resetting it.