I have some waypoints, but I use those largely for ETA and rough direction. I use GPS for speed. I also record and then overlay my trips onto charts, so I can compare what I have seen/experienced with what the charts show. I do that for long distance racing and for my cruising log. I also do this to know where I may have seen something interesting. I can then extract that data, play it back or even use it to generate a way point or two.

For racing I have created waypoints for marks, especially for some of the more complicated SIs that just gives a bunch of marks, but never announces the actual direction or order until just minutes before the race. (Cortez Racing Association likes to do this)

So I have a lot of files that show stuff like the image below, on my home computer.