It jumped out at me because up until a couple of years ago when I started getting T&E guns, all I had ever owned were used guns. The Snubbie from Hell™ was bought new, and that's the only gun I can recall buying new in the past 10 years. Everything else had been used - in many cases for quite some time. It wasn't until I started getting brand new guns that I realized just how important that breaking in period - be it months, years, or decades - was to the functioning of a firearm.And I can make the argument that the none of the small pocket .380's and 9's have been around long enough to trust your life with them, too. They malfunction, and do it fairly frequently, especially when they are new.
Just about *every* semi-automatic that I received had teething issues of some sort. The Ruger LC9 would occasionally light-strike certain ammunition (the SR9c did, less frequently, on the same ammo, RWS 124 grain). The Bodyguard 380 even had one incident where the round failed to ignite. Even the vaunted Smith & Wesson M&Ps had issues with certain types of ammunition not always chambering properly. The lone exception to this, ironically enough, was the oft-maligned SIG SAUER P250 compact, which digested everything from steel cased 230 grain Tulammo to 185 grain Winchester +P frangible ammo with nary a hiccup.
The important thing, getting back to anon's comment, is that it takes more than a box ammo or two in a range session to establish a firearm's reliability. I don't think it takes years and tens of thousands of rounds, but it can't hurt to run a couple boxes of several different kinds of ammunition - including your favorite JHP carry load - through your firearm before pronouncing it reliable. When I've tested new guns, I've tried to put a minimum of 500 rounds through them before the review, and feel most comfortable after 750+ rounds.
Always remember that a firearm is a simple machine, and machines can and do fail. Finding out that the defensive ammo you heard was the greatest thing since sliced bread in the magazines hangs up on the feed ramp of your new carry gun is annoying at the range - but it could be deadly in that one-in-a-million chance you have to use it. Ammunition is expensive - and personal protection ammo is the most expensive kind to shoot - but it's worth a little expense to find out what works.
And, more importantly, to find out what doesn't work.
That is all.