IMO the .25ACP is the equivalent in power of a standard .22LR, but it is more reliable because it is center fire.

It’s reputation as being ineffective comes from the fact that there are virtually no weapons other than “mouse”, “muff”, and “purse” guns chambered for it. These all have short or extremely short barrels. They are very concealable, however.

Those who disagree might think about the fact that many “officers” in the World Wars (I and II) chose to carry .25ACP as personal firearms; many European police agencies issue them to their detectives; and undercover agents everywhere gravitate to it as a back-up.