This is fine if you're not ambitious. You can diddle around and go on cut rate vacations. If I was European, I would probably believe this is the height of living.
If you do what you love, 20 hours a week isn't enough.
Most people don't do what they love or love what they do.
Therein lies the problem.
I'm surprised you like this article Matt, he doesn't allocate any time for being a second rate internet troll.
I'd say it depends on your priorities, and how you define ambitious.
I love what I do for a living, but I don't spend a lot of time doing it (comparatively), because I have other things I love doing just as much, like spending time with my child, and being outdoors.
I have ambitious goals for what I want to achieve with my life, but those ambitions span a lot more than just my career. Many of them don't require money to do, just time, commitment and energy.
Will I make as much money/grow as big a business as if I spent all my time working on it? Of course not. And at some point in my life, it's entirely possible I'll decide I want to shift my priorities.
One isn't better or worse than the other. The important thing is to make a carefully considered choice what part you want your work to play in your life, and then evaluate regularly whether it's doing that.
I've seen plenty of people who go self-employed because they really want more time with their kids, and end up working 60 hours a week. Unsurprisingly, they are miserable. Likewise, people who think they can build a multi-million dollar business following the advise in OP's linked article are bound for disappointment.
