[H] Phone security

[Winterlight]

I do have some apps on my phone that I use but I am really not a big 
smart phone user. If I am mobile I would rather pull out my laptop. 
And I am really not sure about phone security. My phones are updated 
to the current OS, and I use an app called folder lock to protect 
what matters but I never use a phone for online financial matters.

I pay for a private hotspot and VPN service for my laptop and use 
virtual encrypted drives for data, but up to now I don't use VPN for 
my phones. Should I? Is a connection to AT&T or T-Mobile an encrypted 
connection like a VPN would be?  Am I overly paranoid about using my 
phone data connection for banking / credit card matters? Please 
enlighten me. Thanks
w