A skinny follows the leg, so it works with any shoe and is the one that fits under a boot. A wide leg hangs from the hip, so it needs a shoe with some height under it and it needs the right length or the whole line collapses. Wide leg is the more flattering silhouette on most people when the length is right, and the more punishing when it is not. Skinny is the one that always works and never surprises anyone.
The length is the whole thing on a wide leg
A wide leg should just clear the floor in the shoe you will actually wear it with. Too short and the line breaks at the ankle, which is the opposite of what the shape is for; too long and it frays. This is the reason a wide leg looks incredible on some people and shapeless on others, and it is almost never the jeans.
Rise matters more than width
Both of these are high-rise, and that is doing more of the work than the leg shape. A high rise puts the waistband at the narrowest part and starts the leg line higher; a mid rise in either shape is a different garment. If a pair of jeans has never looked right, the rise is the first thing to change.