I considered an iPod Touch for the same reason - was thinking I could just use it on WiFi and it's miles cheaper than a smartphone. Would have considered an equivalent Android device if one existed.
I decided that the real advantage of these smartphones is internet, everywhere. I would not have been satisfied using it only on WiFi. I think you might be surprised at the number of places you will want or would use internet if it were available. I use it constantly - a smartphone has actually substantially changed how I shop, how I use my computer, and how I access information.
I use it LOTS at stores, looking for reviews, comments or prices. When questions bounce into my head, I look them up immediately. I am less attached to my computer because even important stuff (emails, ticket purchasing, work-related stuff) can often be handled on the phone.
Plus I hate carrying multiple devices.
Just my $0.02. Your needs might be different.