Certainly no casino site will invest this entire amount in a single day.
It takes good analytics and marketing tools to choose the right channels at the right times.
Some platform will give more return to the site on weekends, another in festive seasons or else in some quick promotion that the site wants to promote, but they will never happen simultaneously all on the same day in the proportion you estimated.
However, still the values should be astronomical. However, I believe that the return pays off and the profits are greater than what is invested in marketing.