I am not a rotisserie expert, but I do own and use one. It has always been my understanding that its main benefit, compared to just putting a hunk of meat on a grate over some coals, is that you get absolutely uniform browning, and that the meat "self-bastes" as the juices flow around the outside of the meat before eventually dripping into the pan.
For a brisket, even if you are not planning to smoke, but merely to cook it, I'm not sure how important these two things might be. Because of the fat content, I wouldn't think there would be much need for basting, which is usually done to keep meat moist, such as basting a traditional in-the-oven turkey breast. Turkey breast contains very little fat, and therefore benefits from basting. As for the browning, the rotisserie might help but, once again, given the fat content, I'm not sure what sort of result you would get.
I'll be interested to hear from anyone who has actually done this and, if the result is really good, I might give it a go!