Compounding is the easy half. This shows the other half: the fund fee charged on your whole balance every year, and the tax an ordinary account pays that a retirement account does not.
Far more than the headline percentage suggests. A 1% annual fee is charged on your entire balance every year, and the money taken would have compounded too, so the lifetime cost is usually well over double the fees actually paid.
The annual charge a fund takes, expressed as a percentage of the money you hold with it. Crucially it applies to your whole balance, not just to your gains.
An ordinary investment account is taxed on payouts each year and again on the gain when you sell, while a retirement account shelters most of that. Set your own capital gains rate to see the difference for your country.