to a city that is growing in level, you can transport directly (no slow transport) the product that will disappear. when the city grows, you get points for your deliveries.
if you play classic or europe version, you can pay money (or 25 gold) for the passenger wait time. the city grows, you get the points. i keep giving gold (only 100 if possible, but more for later eras when other players also give) per city i am connected, for the passenger wait time, i get points everywhere the city grows!
i dont know what you mean by no point when the city grows ^^; you can always get some points.