Financial mistakes are different from getting hacked due to stupidity, financial goals are to be done using budget strategy because you can't tell which investment will survive in the long run and this is different from you exposing your seed to your wallet online.
Of course it's a financial mistake not to budget and money allocation shouldn't go to investment alone, other aspects of life like housing, cars, debt repayment, entertainment, savings etc all make up for the purpose of budgeting.