Jack does not seem to recommend putting money into a 401k/IRA and especially if it’s not matched by an employer because it’s locked up and he doesn’t trust the government to not pass further rules or taxes against it or say if there is a massive market crash etc. That analysis is echoed by others and seems to cast some serious doubt on 401ks
I'm a lot smarter than I am disciplined. I have bad habits and need to construct silly things for me to behave properly. I won't behave rationally if you set $100,000 in cash on my kitchen table and told me to make "good choices" with it. If instead it's in a brokerage account, then it feels more "business" and somehow I'm responsible.
If we were non-emotional robots, Jack's advice is sound. However the reality is, automatically withholding from your paycheck is psychologically easier for me.
If 15% of my pay check is auto-deposited, I don't think of it as my liquid cash at all. If I were to manually contribute the same into an account, once in a while I might make an "exception" to my rule and buy something else.
Likewise my family uses an FSA. We have relatively high out of pocket medical expenses. But it's not just the tax savings, it's a budget tool as well. Each paycheck $N are held in that FSA account. I also prepay for my routine veterinarian care, for a small discount. I envy people who can save 6-9 months of living expenses in a savings account and resist the temptation to buy a new cordless drill, firearm, ham radio or whatever they are into. For me, keeping that money in a CD, or even a brokerage account is just enough barrier to remind me, it's not play money.