I thought it was because she breathes through her skin.

Because this:

I like Dragon Ball Super.
Novertheless, the greatest thing that bothers me, even beyond the sometimes crappy animation, is how retarded and non-sensical Goku has become.
He was never the sharpest knife in the box, but he wasn’t just plain retarded. It’s hard to think of him as the same character that we had in the Cell…