Why is the best price search not available when I search for connections for today?

When searching on the current day of travel, the slider for activating the best price search is not displayed. The reason for this is that there are usually fewer offers available for the current day, which also differ less from each other in terms of price. However, the best price search compares all prices for an entire day - this is not possible with a daily search, as the day has already begun. This is why the best price search is only offered for future travel days.