Slub Yarn / Effect Yarn

Dear users, dear authors,
I read an article about slub yarn, which seems to be a type of effect yarn with alternating thick and thin sections. Could you explain this in more detail? What are the benefits of using it?

Personally, I find it quite hideous as a fabric.
I don’t like it as yarn either, though it’s more suited for knitters.
It gives knitted pieces “more texture”—I find it terribly “restless.”

The advantage is supposedly that the color and texture come out differently, like little “flames” (hence the name). It’s also supposed to be lighter and airier for summer. But I don’t like it at all. I think it looks kind of messy. And it’s also unpleasant to work with.

Thanks for your input.
If I understand correctly, many of these fancy yarns are just a “matter of taste”? 

Well, visually, I find quite a few of them very beautiful, but I don’t always enjoy working with them. Some are at least easier to knit than to crochet, but others are just fundamentally more than complicated and nerve-wracking.