Benifits of Using a white sealer or base coat

hey whats guys um im painting my truck a bright red with some sort of a graphic and ive used a light grat primer should i use a white sealer before i spray the red or spray just a white base coat then spray the red whats the deal with doing this i know the sealer helps from bleading but will the red appear brighter i just want to know the benifits of using a white sealer or using white as first base coat thanks