I'm no chrony expert so hopefully others will chime in here but, knowing what your velocity spreads are is important. One element to accuracy is consistent loads one after another. It's important to know are my velocity spreads 5 and 10 fps or 50 and 60 fps. So for example I fire 3 shots and chrony them at 2900, 2910 and 2906 I'd be pleased that inaccuracy on the target isn't due to vast velocity spreads. On the other hand if I fire 3 shots and chrony them at 2900, 2937 and 2948 then inaccuracy at the target due to velocities hasn't been eliminated.
Chronys can also be useful in load development for example comparing velocities from one brand of powder, bullet etc to the next.
As mentioned earlier, hopefully others will lend their comments on the subject.