These are supposed to be for retracting the slide for a chamber check (the kind you do to see that you did in fact load the chamber). You reach up under the front of the gun, grasp the serrations with a pinching motion (keep stray fingers away from the muzzle) and draw the slide back slightly, to see a little bit of the brass in the chamber. You do not need or want to draw it back so far that the cartridge gets ejected. Depending on the pistol design, I can grasp a slide in this manner just fine with no serrations at all, but prefer not to do it this way. Instead I hook my thumb under the bottom of the grip "tang" or safety, put my first three fingers on top of the slide between the rear sight and ejection port, and close my whole hand to retract the slide a small amount. This is much easier, especially on a double-action gun that has the additional resistance of cocking the hammer.
I have a CZ PCR (a similar gun to the P-01 except with a tapered-bottom frame that has no accessory rail) with front cocking serrations, and they are completely useless. On this gun - as with all CZ75s - there is little exposed slide to grasp anyway, and I need much more of the "meat" of my hands on it than the pinching motion of my thumb and first two fingers. But at least the front serrations are unobtrusive and don't hurt anything.
