Pistols should work out of the box, ideally.

Sometimes they don't, though.. for a multitude of reasons.

After all they are just small machines.

The break-in gets a misconstrued rap as new shooters shoot new firearms and say "well, it isn't broken in". ...yeah, kind of, but not necessarily.

Most any firearm will function fine from the factory, but the break-in is commonly viewed as essential to diagnose any potential, rare, issues.

I would not carry a pistol to defend my life with "out of the box", and if you wouldn't either-- you may believe in a break-in period