Assuming that one was building a precision-fit target pistol on a Browning-based, tilting barrel system. . .
1. Recoil spring pushes the whole slide forward.
2. Barrel lug engages on the slide stop or locking block and starts lifting upwards to lockup, which occurs not only there, but also. . .
3. At the muzzle where the barrel is ideally fitted to the slide or barrel bushing. . .
4. At the radiused cuts on the slide/barrel in front of the chamber (1911 & BHP), or front of the chamber (Glock, Sig)
5. At the top-rear of the barrel hood against the upper surfaces of the breech face or close to it.
All of that conspires to lock the barrel into as consistent alignment with the slide (containing your sights) as possible for best accuracy. If the goal is to try to do all of that to a semi-decent level of precision, there's enough redundancy to get OK results if one of the areas isn't up to snuff. If you're trying to kick wartime production bullet hoses out the door as fast as possible, the more possible chances you have at "an anchor that can bite sea-floor", the better.
A large number of partial anchors can do a surprisingly good job, but if it's all loosey-goosey and you start omitting some entirely, yeah, the corner-cutting may bite you.