I use it (along with other oils/fats) in cooking from time to time. I lke that it is a drier oil and works well on leafy foods & has next to no aftertaste. As far as losing weight is concerned, I think it just works in the body like any other cold-pressed vegetable oil. It's main fatty acid is linoleic acid. I would not depend on one oil to lose or keep weight off, to be honest. Eating a balance of unprocessed fats is probably best. Because safflower is mainly Omega 6, you ideally ought to balance it out with more Omega 3. Flax and Camelina oils are more balanced when it somes to balancing these out & of course, fish oils/fats if you are not vegetarian.
(Also, flax contains phytoestrogens which is great and very beneficial for some people, but not for others.)