As an on-call incident commander for oil spill response, I find it very useful to have the ICS-201 app right on my phone. My phone is with me all of the time. It is nearly as powerful as a laptop but with the small screen, filling out a PDF or DOC ICS-201 is cumbersome and slow. With the 201 app, data entry is fast and easy. I use headphones so I can still talk on the phone while documenting the event.