Id highly recommended one, especially if you like tinkering with loads.
Like NTS said, mostly why i bought one was for drop data (and to tune my bows), but eventually it turned into a much more versatile piece of equipment for me.
Each new lot of powder, or bullets, i open i run 5-10 over the chrono to see if theres a noticeable change. Usually there isnt but i HAVE seen a few.
I use it to tailor specific loads to a specific hunt. Like using my 7mm stw on 800-1000lb cows at sub 100yd ranges. I loaded 175sgks to 2800fps for that hunt, where as my normal loads were over 3k. It actually took a surprisingly large reduction in powder (and a switch to a faster powder) to get that done with decent consistency. While i could have done it with guess work id have never really known where i was in the velocity spectrum.
I also correlate with quickloads, and other pressure tested reference data to get a rough idea as to what pressure my loads are running. While not precise by any means its another piece of info that helps me with load evaluation.
Then theres all the other intricacies that having a known velocity can help with. Like accuracy nodes, ive seen 2 guns that showed a preference for a specific velocity range. My 7mag being the most annoying, as it would go from about 2"+ at 100, with any bullet over 140, to right around an inch once you broke 3k. Same result with 3 different powders.
My 06 shows a similar pattern but not nearly as significant.
