Luck is clearly pitched at a particularly young demographic, which means this is more of a marketing failure than anything else. Based on the trailer, you'd think this was intended to go up against the likes of Pixar, but in reality the target is more Disney Kids. That's a perfectly fine thing, but it did leave you feeling a little underwhelmed.
Young kids won't mind the repetitive dialogue, simplistic jokes, or paper-thin characterisation/plot/world-building, of course, but it does mean that it feels a little half-baked. Even elements of the animation occasionally feel wonky, or certain voice lines will lack the right ambience and seem transparently layered on top of the visuals, so I think this may have been a reasonably low-budget affair.
That said, though, the best moments in the film are all sold by the animation, and it would be a disservice to claim that this aspect is in any way bad. The bad luck montage for Sam's first day on the job is genuinely very funny and has some excellent observational physical comedy, rather than merely relying on slapstick gags. The same can be said for the real-world chase sequence, where Bob effortlessly glides from one lucky situation to another, constantly keeping a straight, deadpan face, that works so well. In fact, I'd say Bob (the cat) is perfectly animated throughout and is generally a lot of fun as a character.
Unfortunately, that level of detail is otherwise fairly absent. We don't gain a huge amount of understanding about why this "luck world" exists, or how the denizens within it really work (and I'm particularly baffled that the "bad luck" people are largely root vegetables, but maybe that's another "little kid" thing 😂), and the way the plot ends isn't overly satisfying. I'd have loved for the film to explore how a world of nothing but good luck would have actually been slightly dystopian: a world where everyone that plays the lottery wins; where every sports game is a freakish chain of events leading to a drawer; where no one really gets what they need, because everyone gets what they want, that kind of stuff. I'd also have liked them to explain why Sam is quite so unlucky. I mean, she's an orphan, could it not have been possible that she was, in fact, a Bad Luck creature? She could still have had the same ending (indeed, it might have made her and Bob a bit more of a misfit pair), but also help wrap her own misfortune up a little. Also, how is everyone just okay with Bob talking all of the time 😅
That all said, for young kids, it's fun enough. It has a moral (or sorts) and it doesn't do anything too egregious, so overall, it will probably be enjoyable. But if you're over the age of eight, I'd give it a miss.