And admit it, no matter how busy you are you do watch some entertainment once in a while.
Likewise, in 10 minutes you can watch some short youtube video. The point is not that you can sweeten the deal of the 45 minute work-out to make it more bearable, the point is that when faced with 10 minutes of exercise vs 45 minutes of exercise, 10 minutes is a much easier pill to swallow _and_ is infinitely better than 0 minutes.
I'm glad that you have unlimited reserves of willpower and have no trouble with procrastination and as a result can just do any task on demand no matter how seemingly unpleasant it sounds, but unfortunately almost nobody on this planet is like that.
This research is very positive and useful to get people who are currently doing 0 minutes of exercise a week to do 30 minutes of exercise a week, it flies in the face of a lot of "if you don't exercise for at least x minutes a week, you might as well not be exercising" bullshit.
30 minutes of exercise per week (it doesn't really matter if it's high-intensity or not) is really much much better than 0.