One of the things Sprint offers is wifi calling. For example, my folks have a house in the NC mountains. Cellular service is notoriously spotty up there which is why they feel the need to have a landline (which costs them money). With wifi calling, they can get rid of the landline and still have 100% reliable phone service (they'll still keep their DSL). $30 less/mo for a landline AND they can save about $60/mo switching from their current cell carrier to Sprint. Wherever I land (could be up on the mountain or it could be in a city), I WILL have high speed internet so I KNOW I'll have good cell service at the house. My folks travel (they did a 7k mile trip to the west coast and back this year...who knows where they'll go next year) and we know that cell service gets worse the farther they go away from interstates/major cities. Sprint is as good a "happy medium" as they'll get. Unless I get back in a truck (which is doubtful but possible), I won't have high speed internet but should be able to stay pretty close to major traffic lanes. We'll see.
You are right about VZ being (much) more expensive. I think I figured service for 3 lines via VZ (with unlimited voice/text/data) would run pretty close to $175/mo. Sprint offered the same for $100/mo (plus the cost of my phone, of course). Couldn't really beat that.