It's a fickle business. If the right opportunity comes up, I can see why she would be tempted. And she has a fantastic face/skin so endorsing a cosmetics company would be a sound and credible brand match for her. Must be a really exciting time for her after all her success she's had over the last year.
I'm sure she'll be able to live with the 'hypocrisy' charges
and as long as the focus is still her music, then no biggie.