A little corset sperg:
A fat person doesn’t wear a corset to look skinny. They usually want to wear one to not look like a formless tub of lard so yeah, while the rolls are being “shifted around”, there’s the creation of a waist, which is ultimately the goal no matter how voluptuous you are. Also, corsets come in an enormous amount of sizes and shapes. Everyone can wear a corset, but a fat person probably wouldn’t get a tight-lacing corset. Which is different from a cincher, a wasp, a bodice or the other different shapes of corsets. Choosing the wrong corset for your body type will make sure that no matter your size, you’ll look ridiculous.
I’m on phone so I don’t know how to spoiler sorry.