SMS is all very interesting but it is not 2013 any more so there is no need to send an SMS (paying people on the way) when you can just send an email. It still pops on the person's phone as a new message (at least in Android world, no idea how those iPhones work). Email also has better delivery, speaking as someone in a poor reception area I cannot reliably receive messages, however, wifi works pretty good at home and I can get emails with that whereas wifi does me no favours for SMS.
A few years ago I did have SMS for my own version of an uptime monitor, however, when my credits ran out I didn't miss the SMS messages at all (my script also emailed). That led to my 'discovery' that being able to send an SMS from a bit of code might be impressive however it is also not that useful in the first world. Maybe this product is better suited to dogs in the developing world somewhere.