You would be surprised at the number of generally math-savvy (at least “enough”) people who have an irrational fear of “what if it goes down?” and fritter away decades of substantial growth (with each foregone decade skipping roughlh modeled as a missed doubling).
Savings accounts and similar are the appropriate place to put cash you’re saving for a specific purpose or for emergency funds. You don’t want to invest something you will or could need access to in the short term.