In my current position, I now have to attend telecons on a somewhat frequent basis. Having to wait until the telecon admin sets up the call, while it doesn't take long to do, can be an inconvenience if you have to dial in several times until the call has been set up. Being able to start it from a mobile device saves time and you don't have to risk missing out on the beginning of the call because you were waiting for the call to start to dial in.