^^^^
.25ACP's were made for TINY pocket pistols with barrels of around 2". You can't even compare a Colt Vest Pocket size-wise to a Seecamp, NAA Guardian 32, or Kel-Tec P32 (which all happen to be some of the smallest, lightest pistols around). I have all of the above, except for the Seecamp, and the NAA and P32 covers the Colt - not to mention the width.
All those that say that they would rather have a .22LR pocket pistol are mistaken. Out of something like a Beretta 21, the .22LR has slightly less (even with Stingers) "umph" (if one can even say that), than a standard 50gr 25ACP out of a Colt Vest Pocket. Hypothetically bringing down the Beretta to a 2" barrel, and the .25ACP wins hands down and that's not even talking about centerfire -vs- rimfire or heeled -vs- crimped.
As an aside, I have no idea why folks would knock the .25ACP pocket protectors but would not hesitate to say they would carry a .22LR of the same size.