The only difference is the hamster doesn’t pretend the morning run was enjoyable
Like every sport, it’s not for everyone. If you don’t enjoy running you don’t have to do it.
I personally find the easy runs relaxing for the brain, and not taxing on the body, and the hard runs are quite fun.
You move weight around, later you move the same around a bit more (yay!), or move a heavier weigh around (yay!).
You get to really know what your body is capable of.