[gwbas1c]

No, "an index fund that tracks the S&P 500" is more like cruise control.

Self-driving money would basically take all your income, and decide if it's best to invest in such index fund, or pay off your mortgage early.

I always pay off small, low-interest loans faster, because I get tired of juggling the money. If I had "self driving money," it would continue to "write the check" for me as long as it can find a better investment vehicle for my remaining money.

[wait_a_minute]

It's not possible to automate a decision like investing more vs paying off mortgage early, because that decision is entirely up to your personal preference.

Do you prefer being debt free, or do you prefer keeping some debt that is at 3.6% interest while you earn 7% in the market? The former has a lower risk associated with it whereas the latter has a higher potential for net worth increases over time. But to decide which one you want, you'd need to figure out what your priorities are. A machine can't do that for you.

At best it could show you the outcomes if you were to pursue either path, given some set of assumptions. But a machine also can't predict the future so it wouldn't know what the absolute correct answer is.

The reason the S&P 500 tracking is more like self driving is because the economy will likely be worth more in the future than it is today, and so will investments made into index funds. It's possible the economy could be worth less, but if that happens we'll have much bigger problems to deal with than individual net worth.