Molasses has quite an interesting political history regarding the distilling of rum which is well worth learning about if you have a minute...in the meantime here's some basics on flavor:
Molasses and Treacle are pretty much similar products, both are consequences of sugar production, whether cane, beet or other source. Molasses is what you get after several boiling processes. When I taste molasses, I think of black licorice, which I loved as a kid; which makes sense because traditionally black licorice was made from blackstrap molasses. As an adult I’m not so into black licorice anymore but I am a huge fan of things like gingerbread and sticky toffee pudding!
For me the flavor draw comes from the complexity of sweet, bitter, and almost earthiness. I don’t necessarily like cakes and pastries because they always seem too sweet; however, if it has molasses in it, it tends to minimize that sweet edge, adding a slightly savory quality and then I can’t get enough of it.
From a culinary perspective molasses is not only for baked goods, it can be found in things like baked beans, sweet and sour sauces, and barbeque.
From a health perspective molasses is sadly still considered sugar, so limiting it is a good idea. However, it has its good points. It is high in minerals and can even help if you tend to suffer from things like anemia or other hormone imbalances. It is full of antioxidants that can help fight against oxidative stress (I know, seems counterintuitive that a sugar product could help with oxidative stress). Studies also suggest molasses can be useful in promoting healthy, strong bones, as well as contributing to digestive balance.
I can’t recommend high consumption of molasses or treacle because it is still at the end of the day a sugar product. However, the occasional use can be beneficial. I have been known to stir a spoonful in hot lemon water or even coffee which is a nice change.
The caveat: Make sure it’s unsulfured and organic...otherwise the unnamed chemicals used during processing make any benefits totally null and void.