Why bother with SMS when everyone has a smartphone these days? The point is when a new employee gets a brand new phone of the shelf it's not configured what so ever. Now you do know the phone number but that's it. Therefore, email is not an option and you're left with SMS to onboard the employee using XenMobile. I haven't really seen many companies who have their own SMS-Gateway. This is where email to SMS is a simple and quick option to do the job.