it automatically takes some major trigger foods out of the equation (red meat, dairy) but it can also make it quite difficult to find safe options at restaurants (seafood is sometimes the only thing I can order without worry).
Vegans are going to get a lot more plant foods, which means fiber, in their diet. Great for overall health, but you'd have to be extra cautious with the insoluble fiber.
You can manage IBS whether carnivore, vegetarian, or vegan, as regardless you'll be excluding the same trigger foods and watching your soluble vs insoluble fiber. For other health concerns, being vegan is probably the very best way to go.