I mean no disrespect, but this reads a bit like an over-confident take of a person who never went through a financial calamity. A bit like leveraged house-flippers of 2006. The value of your margin loan collateral can plunge suddenly. The rates and the terms of your credit card debt can change overnight. You can get hit by unexpected and urgent expenses - adverse judgments, emergency home repairs, etc - and that's bad news when you're already maxing out your credit lines.

Debt is a useful tool, but it's also dangerous. It's one thing if you're using it to advance some important cause... you know, making a big bet on a business idea, making your dreams come true. But if you're taking risks for, as the author puts it, "consumption smoothing"... there's a good chance of ending in trouble for no good reason.

Plus, we're not hyper-rational robots. Spending money is habit-forming. It's often about gratification, about social standing, about competing with peers. Especially for younger folks, and especially for people in the Bay Area, where we often look up to people who essentially won the startup lottery or ended up getting lucky in some other way. Instead of "consumption smoothing", it's often better to ask if that consumption is useful to begin with.