Well, let's start with the fact that stretch marks are primarily the result of weight gain, not weight loss. Stretch marks or stretch marks also occur due to genetic factors or from very heavy physical exertion, and very often in women due to pregnancy. But a competent approach to business: sufficient skin moisture, proper nutrition, an active lifestyle solve all issues. Plus, of course, there are already methods to remove such problems. So I wouldn't bother with that.
I would not say that stretch marks are beautiful, but, in general, in partners I am interested not only in the state of their bodies. If we got to bed, I was probably interested in something else in the girl (or I'm drunk as an insole and won't notice any stretch marks). And, of course, darkness is a friend of youth: if you are embarrassed by some details of your own appearance, it is not necessary to let your partner look at them.
Neither this drawback, nor any others, nor those advantages that are not visible to the eye of a stranger. Just because this is not a topic for communication with friends, and, from my point of view, not too decent.