Nice advice for the original target audience of people with lots of spare time who have already sorted out where the rent money is coming from.
For the other 90%+ of us not so relevant.
If people don't have rent money they don't have the time to work on open source as they are too busy working (i.e. in a short-term job unrelated to developing software). So the advice only applies to people who are financially stable but also have spare time such as students.