Never underestimate the choices of lazy people. Throughout the years the human race has gotten used to the centralised control of the banks and them 'helping' us when we make mistakes. You forgot your PIN, no problem call your bank. You can't find your card after a night out, don't worry about it, just call your bank!
And now this new technology appears where no bank has control over you, you are the manager of your own funds and make all the decisions yourself. But people don't see the good but tend to focus on the bad. The bad is, if you lose your private keys your funds will no longer be accessible to you. If you don't write down your seed phrase properly your funds are lost. People would rather take a risk and use a website as their wallet because it is easier and quicker, you don't have to download the blockchain or write down weird word combinations etc.
They are thinking, nah what are the chances that someone steals my money? it will never happen!
And then...