They could have also sunk all of the equity into index funds, and done the digital nomad thing [1], using investment income to boost quality of life.

I believe the point is, don't waste income on servicing housing debt unnecessarily (efficient use of capital). If jet skis and McMansions are your thing, cool. If you'd rather party it up in Medellín, Columbia while living off of dividends, also cool.

[1] https://nomadlist.com/cost-of-living/in/