There's a lot of bluster about "mouse guns", the real truth is, the smaller caliber is going to keep you on target faster, and 4 or five hits with a 22 or 25 is far better than less accuracy, and less rounds, with a larger caliber.
OTOH, not so much with 22s, but 25 caliber firearms are small, in the extreme. They look like a toy, or a novelty cigarette lighter, or something. So there's about zero deterrence factor, in pulling your 25ACP, if you pull it, you're probably going to have to shoot it. When I carry my Governor, it's impressive size just may have a deterrent factor, at the last second, the attacker may have a sudden change of heart, and flee, because the gun is a serious handful. I would far rather pull a large gun, and not have to shoot, than pull a small gun, and have to unload it, into some unfortunate putz.