It depends. Really it's the nature of the mission that determines what kind of weapon a SEAL would want to use when operating on the field. A squad assault weapon would be good for use when one is in a larger team in which the operators have a larger variety of weaponry. Again, it depends on the role that one is playing within the team. Being able to hold sustained suppressive fire on a target is very useful in a pinch, and can sometimes be the difference between life and death for squadmembers. While a SEAL certainly wouldn't want to go into a close-quarters situation with a SAW, I could see how it would serve as a boon when acting as a lookout or covering other squadmates.