Context is important. Anything is better than nothing and a .22LR still beats a sharp stick most of the time. Hunting is different than self defense. Bullet placement is important. Most of us remember when Guns and Ammo would print those big special magazines on narrow topics. I remember one about the .22. One story in particular. It took place in Kenya during the Mau Mau uprising 1952-1960. The Mau Maus were attacking white (British) ranches and farmsteads so the police, constabulary and military units were going out to all of the isolated ranches to warn and evacuate the residents. In this account, they were headed to a ranch house where they knew the wife was normally alone during the day while her husband and sons were out working. As they approached the house, they found bodies. 9 or 10 dead Mau Mau. Each of them with a single .22 hole to the forehead. It seems that the woman commonly entertained herself after her work was done, by shooting leaves off the trees with her .22LR Colt Woodsman pistol. Suffice to say, she got pretty good and she headshot the approaching Mau Mau until the survivors decided their magic that turned bullets into water wasn't working and went someplace easier.
The second is personal to a degree. I grew up in Alaska and every once in awhile, there was a report of dead moose being found in town after being shot with a .22. That same Guns and Ammo also had a story of an Indian hunter who routinely killed moose and bear with a .22. He would stalk them carefully, and shoot them through the side, between the ribs. The story said that he got lung hits, so I have to assume that if he got a rib, he'd take another shot until he saw some foamy blood from the nostrils. He didn't get quick kills, but eventually the animal would bleed out internally, fall over, and die. He used a .22 because it didn't make enough noise to annoy them and the wound felt like a sting to them. Again, context is important. He didn't shoot a charging animal to defend himself, and these were not quick, humane kills.
Finally, the same magazine discussed the effectiveness of the .22 bullet. Take it for what it's worth, but they said that .22 should not be underrated because the bullet did unexpected things. It would bounce off bones and change direction. The long, soft bullet would bend when it glanced off, and a shot to the chest could exit near the hip, hitting lots of stuff on the way. With regards to the aforementioned Israeli kills, velocity from a short barreled pistol would usually get through the skull, but not through the other side. So there could be some internal ricochet brain damage.