They are fun to see what you have AFTER working loads. They tell you nothing about pressures or accuracy. All those other numbers you get only tell you if the burn rate is efficient.
You can find good numbers even if 1000 fps away from what the gun wants, bullet to twist fit and spin rate for that bullet.
Accuracy is never found by looking at those numbers.
All guns are different too, some slower, some faster with the same loads.
Some guys use them to try and reach book velocities even if they need to over load---just because, the book said so!
The best thing to do is get off the velocity kick, 100 fps more means nothing at all for trajectory and an animal has never felt the difference. Accuracy first so you can hit the animal.