Barely -- that's an hour long walk for most people. Given the choice between walking and biking for 3 miles, I'd bike. I used to have a 2.5 mile commute that I did by bike. I'd occasionally walk, but didn't normally want to spend that much time.

I'd use a push scooter up to 5 miles if it's convenient. One can fold it and take it on a bus or train.

Runnable: 5 km ~ 25 mins

8 minute miles with a backpack with a laptop and a change of clothes? Perhaps for some people, but not everyone.