For me claw machines require little skill to play, as everything depends from how owner set claw strength. User can simply randomly move controller and randomly choose item. If claw closing strength is enough, it will hold the prize like close grip. But in most cases we see how claw shakes and drops the prize the next second claw was closed. However that is ok. Low skill requirement is perfect for everyone to try to win the prize.
I think of it a bit as of fair games. Everything is kinda set up for the player to lose but still being a bit close to winning.
Very similar to gambling. But in my mind there is the difference that the outcome is not generated at random. There is some level of skill involved.
I would call claw machine a very light version of gambling. Because it might cause interest, but not addiction. Never heard that someone is addicted to claw machines. It is easy to stop. And when you get that prize, you stop gambling and it does not motivate you to continue. Greed factor is very little in this case.
I see that South Park has mentioned it can develop addiction among kids, but from what I saw, kids stop when they get a plushie prize. After getting a toy, I have never seen them asking for more or other. They focus on one specific, you get it for them and you are a hero for the rest of the day.