The .25 acp was likely designed with the unreliability of rimfire ammo in mind... If offers similar ballistics to the .22 lr while being reloadable.
Actually, IIRC another primary factor was that the .25ACP cartridge was designed around the turn of the 20th century when black powder .22LR ammo was still commonplace.
Since .22LR uses a heeled bullet- i.e. the body of the bullet is the same diameter as the case- the bullet must be shoved through the powder residue left by the previous shot; consequently, black powder .22LR basically won't work in semi-automatic firearms because the powder leaves so much residue behind that subsequent rounds won't chamber. The shooter would have to cease firing and clean the gun after only a handful of shots.
It's obvious why this wouldn't work in a defensive firearm.
This is also the reason that Winchester's first semi-auto rifle, the Model 1903, used a proprietary rimfire round with comparable ballistics to .22LR- the .22 Winchester Automatic. This round was exclusively loaded with smokeless powder to ensure that the gun would function reliably.