It’s about smoothing you, not compressing you to look a size smaller than you really are.
I have ten of these and wear them every single day under everything. These are all I own (no bras or panties). So, so comfortable and smoothing:
@ChoatieMom That doesn’t give you an obvious panty line? I wear a thong under pants and some sort of boy short under dresses because I don’t like that line right at the butt cheek. :))
I would not wear any shaper daily - those are for special occasion dressing. Boyshorts are great under pants for making the panty line disappear. I am not a fan of thongs aka self-inflicted wedgie. 
No lines that I’m aware of, that’s kinda the point. The shapers are very smooth. But, I’ve never worn a thong or bikini underwear in my life, so what do I know?