Almost every protein that I consume is weighed raw for ease in logging. One reason is if you are cooking a dish with e.g. bacon as an ingredient, you may not be able or want to separate it out at the end. Likewise, if I sauté chicken breasts in a pan and then finish the dish with other ingredients, I probably want to just eat the food and not deal with weighing them after water loss. Providing both just provides greater ease in logging your meals and is exact-enough for most people :)