As somebody already said, a smart phone is not a NECESSITY to run a business. But, if you and I are in the same neighborhood, and I get that email from a homeowner on the street, asking for a quote, I will respond immediately and possibly get the job, especially if I am on the street, I can do the lawn TODAY. My business won't tank with out a smartphone....I actually do not have one, but just ordered a Galaxy S2 from sprint....but I do believe that I will be more EFFICIENT in using my smart phone in conjunction with the software that I use to run my business.
In the end, if I can do things more efficiently, I can be more competitive with my pricing and still make the same money as those that need to charge more. Uh Oh, now I started an argument on low balling! LOL