"policy recommendations require a consideration of both costs and benefits and we have made no attempt to calculate the economic benefits of using mobile devices while driving. We acknowledge, though, that identifying any economic benefits of playing Pokémon GO while driving stretches our imaginations"

They narrowed it down to just driving.

It's a bit weaselly to not try and find the value.

Napkin Maths, a movie is $5 per hour. Driving for a hour playing Pokemon Go is worth ~$5. But it's also worth ~$5 per hour walking. So the Napkin Maths fails.