Looks like you want a tunic made of sweatshirt material, not a long sweatshirt. Different cut & fit. I personally prefer a sweater over my leggings with boots but if I found a tunic like you linked to in my size I'd probably grab one.
ETA: IMO leggings are thin enough to be worn under skirts. If they're too thick for that, with or without a zipper a/o buttons, they're pants.
ETA: IMO leggings are thin enough to be worn under skirts. If they're too thick for that, with or without a zipper a/o buttons, they're pants.