With the app, there is no going to the calendar, trying to find where you put the PIN/ID number needed to log into the call, getting the right access number, switching to the dialer and placing the call. All you need to do is press one button. On a Windows Phone 8 phone, you can even use voice command to join the conference call. Simply press down the Windows logo and say "conference join". The app figures out which call is about to start or which one is in progress and repeats it back so you can confirm it. If you company uses Lync, the Lync app will automatically launch.
It isn't magic or even witchcraft. Nokia has many companies conference call settings stored on its servers and if not, you can set it yourself and share the info with Nokia to help your fellow co-worker. If you make a ton of conference calls a year, you might want to check out the free app at the Windows Phone Store.
source: NokiaConference(Beta), Nokia via WindowsPhoneCentral