Well, its useful for hard- to solve equations- such as distance based equations, and that really does prove useful.

Really?

Yes- for example, if you were asked for an expression for the total flying time for a distance of 1610 km from Miami to Wahsington, and then another 634 km to Tronoto, based on the speed, could you solve it?

No....

Well, with this you can, and that makes it useful.