Neat write-up, but I feel the primary usage of a smartphone is for when you're NOT connected to WiFi. I can use Google Voice / Hangouts to make calls from my laptop. Do you carry a hotspot or anything for on-the-go use?
The plan is $20 for 1GB/mo of LTE data, so you can make calls and use data on the go. I might not have been clear enough about that in the post.